#include "bits/stdc++.h"
using namespace std;

#define REP(i, n) for(int i=0; i<(n); i++)

signed main()
{
    int ans = 1;
    string s;
    char c;
    while(true) {
        scanf("%c", &c);
        if (c == '\n') break;
        s.push_back(c);
    }
    REP(i,s.size()) {
        ans <<= 1;
        if (s[i] == 'R') ans++;
    }
    cout << ans << endl;

    return 0;
}