#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define REP(i, n) for(int i = 0; i < n; i++)

int main() {
    string s;
    cin >> s;
    ll ans = 1;
    REP(i, s.size()) {
        if (s[i] == 'R') {
            ans = ans * 2 + 1;
        } else {
            ans *= 2;
        }
    }
    cout << ans << endl;
    return 0;
}