#include <bits/stdc++.h>

using namespace std;

int main() {
    string s;
    cin >> s;

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