#include "iostream"
#include "algorithm"
using namespace std;

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