#include <bits/stdc++.h>
using namespace std;
string ch;
int b[1000001],ans;
int main() {
    cin>>ch;
    int n=ch.size();
    for(int i=0;i<n;i++){
        if(ch[i]=='R'){
            b[i+1]=b[i]+1;
        }
        else{
            b[i+1]=b[i]-1;
        }
    }
    for(int j=n;j>1;j--){
        for(int i=0;i<j;i++){
            if(b[i]==b[j]){
                ans=max(ans,j-i);
            }
        }
    }
    cout<<ans;
    return 0;
}