#include <iostream>
#include <string>
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;
}