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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
 
    string s; cin >> s;
    int answer = 1;
    for(auto c : s){
        answer <<= 1;
        answer += c=='R';
    }
    cout << answer << endl;
}