#include <iostream>

using namespace std;

int main() {
    int a = 1;
    string s;
    cin >> s;
    for (size_t i = 0; i < s.size(); ++i) {
        a *= 2;
        if (s.at(i) == 'R') a++;
    }
    cout << a << endl;

    return 0;
}