using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
namespace AtCoder {
class MainClass {
//C#7.0
string X;
void Solve() {
io.i(out X);
int sC = 0;
int dC = 0;//消したpair数
for (int i = 0; i < X.Length;i++){
if (X[i] == 'S') sC++;
else{
if(sC>0){
dC++;
sC--;
}
}
}
int ans = X.Length - dC * 2;
io.o(ans);
}
public static void Main(string[] args) { new MainClass().Stream(); }
IO io = new IO();
void Stream() { Solve(); io.writeFlush(); }
}
class IO {
string[] nextBuffer; int BufferCnt; char[] cs = new char[] { ' ' };
StreamWriter sw = new StreamWriter(Console.OpenStandardOutput()) {
AutoFlush = false
};
public IO() { nextBuffer = new string[0]; BufferCnt = 0; Console.SetOut(sw); }
public string next() {
if (BufferCnt < nextBuffer.Length) return nextBuffer[BufferCnt++];
string st = Console.ReadLine();
while (st == "") st = Console.ReadLine();
nextBuffer = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
BufferCnt = 0;
return nextBuffer[BufferCnt++];
}
public char nextChar() { return char.Parse(next()); }
public int nextInt() { return int.Parse(next()); }
public long nextLong() { return long.Parse(next()); }
public double nextDouble() { return double.Parse(next()); }
public string[] arr() { return Console.ReadLine().Split(' '); }
public char[] arrayChar() { return Array.ConvertAll(arr(), char.Parse); }
public int[] arrayInt() { return Array.ConvertAll(arr(), int.Parse); }
public long[] arrayLong() { return Array.ConvertAll(arr(), long.Parse); }
public double[] arrayDouble() { return Array.ConvertAll(arr(), double.Parse); }
private bool typeEQ<T, U>() { return typeof(T).Equals(typeof(U)); }
private T convertType<T, U>(U v) { return (T)Convert.ChangeType(v, typeof(T)); }
private T suitType<T>(string s) {
if (typeEQ<T, int>()) return convertType<T, int>(int.Parse(s));
if (typeEQ<T, long>()) return convertType<T, long>(long.Parse(s));
if (typeEQ<T, double>()) return convertType<T, double>(double.Parse(s));
if (typeEQ<T, char>()) return convertType<T, char>(char.Parse(s));
return convertType<T, string>(s);
}
public void i<T>(out T v) { v = suitType<T>(next()); }
public void i<T, U>(out T v1, out U v2) {
var a = arr(); v1 = suitType<T>(a[0]); v2 = suitType<U>(a[1]);
}
public void i<T, U, V>(out T v1, out U v2, out V v3) {
var a = arr(); v1 = suitType<T>(a[0]); v2 = suitType<U>(a[1]);
v3 = suitType<V>(a[2]);
}
public void i<T, U, V, W>(out T v1, out U v2, out V v3, out W v4) {
var a = arr(); v1 = suitType<T>(a[0]); v2 = suitType<U>(a[1]);
v3 = suitType<V>(a[2]); v4 = suitType<W>(a[3]);
}
public void ini(out int[] a, int size) {
a = new int[size]; for (int i = 0; i < size; i++) a[i] = nextInt();
}
public void ini(out long[] a, int size) {
a = new long[size]; for (int i = 0; i < size; i++) a[i] = nextInt();
}
public void ini(out int[] a1, out int[] a2, int size) {
a1 = new int[size]; a2 = new int[size];
for (int i = 0; i < size; i++) { a1[i] = nextInt(); a2[i] = nextInt(); }
}
public void ini(out string[] a, int size) {
a = new string[size]; for (int i = 0; i < size; i++) a[i] = next();
}
public void inii(out int[] a, int size) {
a = new int[size]; for (int i = 0; i < size; i++) a[i] = nextInt() - 1;
}
public void inii(out int[] a1, out int[] a2, int size) {
a1 = new int[size]; a2 = new int[size];
for (int i = 0; i < size; i++) { a1[i] = nextInt() - 1; a2[i] = nextInt() - 1; }
}
public void inii(out int[,] a, int size) {
a = new int[size, size];
for (int i = 0; i < size; i++) for (int j = 0; j < size; j++) {
a[i, j] = nextInt() - 1;
}
}
public void o<T>(T v) { Console.WriteLine(v); }
public void o<T>(params T[] a) { foreach (T v in a) Console.WriteLine(v); }
public void o<T>(List<T> l) { foreach (T v in l) sw.WriteLine(v); }
public void ol<T>(T v) { Console.Write(v + " "); }
public void ol<T>(params T[] a) {
foreach (T v in a) Console.Write(v + " ");
Console.WriteLine("");
}
public void YN(bool f) { Console.WriteLine(f ? "YES" : "NO"); }
public void Yn(bool f) { Console.WriteLine(f ? "Yes" : "No"); }
public void yn(bool f) { Console.WriteLine(f ? "yes" : "no"); }
public void br() { Console.WriteLine(""); }
public void writeFlush() { Console.Out.Flush(); }
public string pad0<T>(T v, int n) { return v.ToString().PadLeft(n, '0'); }
}
class Mat {
public int mod = 1000000007;//10^9+7
public long Pow(long a, long b) {
if (b == 0) return 1;
if (b % 2 == 1) return (a % mod * Pow(a % mod, b - 1) % mod) % mod;
else return Pow(a * a % mod, b / 2) % mod;
}
public long Fact(long n) {
return (n != 0) ? (n % mod * (Fact(n - 1) % mod) % mod) : 1;
}
public long C(long n, long r) {
if (r == 0 || n == r) return 1;
else return (Fact(n) % mod * Pow
((Fact(n - r) % mod * Fact(r) % mod) % mod, mod - 2) % mod) % mod;
}
public long Sum(params long[] a) {
return a.Aggregate((v, next) => (v % mod + next) % mod);
}
public int GCD(int a, int b) {
if (a < b) Swap(ref a, ref b); return b == 0 ? a : GCD(b, a % b);
}
public int GCD(int[] array) { return array.Aggregate((v, next) => GCD(v, next)); }
public void Swap<T>(ref T a, ref T b) { T tmp = a; a = b; b = tmp; }
public T Max<T>(params T[] v) { return v.Max(); }
public T Min<T>(params T[] v) { return v.Min(); }
public double Dis(int x1, int y1, int x2, int y2) {
return Math.Sqrt(Math.Pow((x2 - x1), 2) + Math.Pow((y2 - y1), 2));
}
public int Digit(long n) { return (n == 0) ? 1 : (int)Math.Log10(n) + 1; }
public int Clamp(int n, int a, int b) { return (n < a) ? a : (b < n) ? b : n; }
public long Clamp(long n, long a, long b) { return (n < a) ? a : (b < n) ? b : n; }
public double Clamp(double n, double a, double b) {
return (n < a) ? a : (b < n) ? b : n;
}
public long Tousa(long a, long d, int n) { return a + (n - 1) * d; }
public long TousaSum(long a, long d, int n) { return n * (2 * a + (n - 1) * d) / 2; }
}
class AssociativeArray<T> {
public Dictionary<T, int> dic;
public void init(T[] a) {
dic = new Dictionary<T, int>();
for (int i = 0; i < a.Length; i++) {
if (!dic.ContainsKey(a[i])) dic[a[i]] = 0; dic[a[i]]++;
}
}
public int ValueSum() { int s = 0; foreach (var i in dic) s += i.Value; return s; }
public int KeyNum() { return dic.Keys.Count; }
public int Max() { return dic.Values.Max(); }
public int Min() { return dic.Values.Min(); }
public T MaxKey() { return dic.First(d => d.Value == Max()).Key; }
public T MinKey() { return dic.First(d => d.Value == Min()).Key; }
public bool isContainsK(T k) { return dic.ContainsKey(k); }
public bool anyContainsK(params T[] k) {
bool f = false;
foreach (T v in k) f |= isContainsK(v); return f;
}
public bool allContainsK(params T[] k) {
bool f = true;
foreach (T v in k) f &= isContainsK(v); return f;
}
public void Show() { foreach (var v in dic) { Console.WriteLine(v.Key + " : " + v.Value); } }
//:sort->array
}
class Time {
public bool isLeapYear(int y) {
return (y % 400 == 0 || (y % 4 == 0 && y % 100 != 0));
}
}
class BucketSort {
public int[] bucket;
public void Init(int[] a) {
bucket = new int[a.Max() + 1];
for (int i = 0; i < a.Length; ++i) ++bucket[a[i]];
for (int i = 0, j = 0; j < bucket.Length; ++j)
for (int k = bucket[j]; k != 0; --k, ++i) a[i] = j;
}
}
//Ex
static class StringEX {
public static string Reversed(this string s) {
return string.Join("", s.Reverse());
}
public static string Repeat(this string s, int n) {
return string.Concat(Enumerable.Repeat(s, n).ToArray());
}
}
static class CharEX {
public static int toInt(this char c) { return int.Parse(c.ToString()); }
}
static class ArrayEX {
public static T[] Sort<T>(this T[] a) { Array.Sort(a); return a; }
}
}