#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int N;
  int ans = 1;
  string s;
  cin >> s;

  rep(i, 0, s.size()) {
    ans *= 2;
    if (s[i] == 'R') {
      ans++;
    }
  }

  cout << ans << endl;
  getchar();
}