#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>

using namespace std;

int main() {

    string S;
    cin >> S;
    long N = S.size();
    long res = 1;
    for (int i = 0; i < N; ++i) {
        res *= 2;
    }

    for (int i = 0; i < N; ++i) {
        if (S[i] == 'R') {
            long tmp = 1;
            for (int j = 0; j < N - i - 1; ++j) {
                tmp *= 2;
            }
            res += tmp;
        }
    }

    cout << res << endl;
    return 0;

}