#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main() {
  string s;
  cin >> s;
  int cnt = 0;
  int node[31] = {};
  node[0] = 1;
  for (int i = 1;i < s.size() + 1; ++i) {
    cnt += node[i - 1];
    node[i] = node[i - 1] * 2;
  }
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] == 'R') cnt += node[s.size() - i - 1]; 
  }
  cout << cnt + 1 << endl;
  return 0;
}