#include <bits/stdc++.h>
using namespace std;

int main() {
    long long ans = 1;
    string S;
    cin>>S;
    if (S == "\n"){
        cout<<1<<endl;
        exit;
    }
    for (int i = 0; i < S.size();i++){
        ans *= 2;
        if (S[i] == 'R'){
            ans += 1;
        }
    }
    cout<<ans<<endl;
}