#include <iostream>

using namespace std;


int main(){

  string s;
  cin >> s;
  int n,tmp;
  n = s.size();
  tmp = 1;
  for (int i = 0; i < n; i++) {

    if( s[i] == 76) {
      tmp = 2 * tmp;
    } else {
        tmp = 2 * tmp + 1;
    }
  }
  cout << tmp << "\n";
  return 0;
}