#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>

#define ALL(x) (x).begin(),(x).end()

using namespace std;

int main() {
    string s;
    cin >> s;
    int ans = 1;
    for(int i = 0;i < s.length();i++){
        ans *= 2;
        if(s[i] == 'R')ans++;
    }
    cout << ans << endl;
    return 0;
}