#include <iostream>
#include <string>
using namespace std;
int main(void){
    // Your code here!
    string s;
    cin >> s;
    int len = s.length();
    int current = 1;
    for(int i = 0; i < len; i++) {
        if(s[i] == 'R') {
            current = current * 2 + 1;
            
        } else {
            current = current * 2;
        }
    }
    cout << current;
    
}