堆栈操作合法性

#include <iostream>

using namespace std;

int main()
{
    int n,c = 0,m;
    cin>>n>>m;
    string s;
    while(n--)
    {
        cin>>s;
        c = 0;
        for(int i = 0; i < s.size(); i ++)
        {
            if(s[i] == 'S')
            {
                c ++;
                if(c > m)
                    break;
            }
            else
            {
                c --;
                if(c < 0)
                    break;
            }
        }
        if(c == 0)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
    }
}