using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;

class Prog
{
    public Prog() { }
    public static int Main()
    {
        new Prog().calc();
        return 0;
    }

    Scanner cin;

    public void calc()
    {
        cin = new Scanner();
        string X = cin.next();

        int len = X.Length;
        int pos = 0;

        bool succ = false;
        int scnt = 0;
        int ret = 0;

        for(int i = 0;i<X.Length;i++)
        {
            char c = X[i];
            if(c == 'S')
            {
                if(!succ)
                {
                    scnt = 0;
                }
                succ = true;
                scnt++;
                ret++;
            }
            else
            {
                // T;
                succ = false;
                if(scnt > 0)
                {
                    scnt--;
                    ret--;
                }
                else
                {
                    ret++;
                }
            }
        }

        Console.WriteLine(ret);

    }
}


class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }

}