#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
const int MOD = 1000000007;

int main(){
    string s;
    cin >> s;

    int k = 1;
    REP(i,s.size()){
        k*=2;
        if(s[i]=='R') k++;
    }

    cout << k << endl;
    return 0;
}