#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000000009
#define INF 1000000000
#define LLINF 2000000000000000000LL
#define PI 3.1415926536

#define SIZE 101

int main(){
    int ans=1;
    string S;
    
    cin >> S;
    
    for(int i=0;i<S.size();i++){
        ans*=2;
        
        if(S[i]=='R')
            ans+=1;
    }
    
    printf("%d\n",ans);
    
    return 0;
}