#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
using ll = long long;
using namespace std;
const int INF = 1e9;

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

    ll ans = 1;
    rep(i,S.size()){
        ans *= 2;
        if (S[i] == 'R')
            ++ans;
    }

    cout << ans << endl;

    return 0;
}