#include<stdio.h>

int beki2(int n){
  int i, re = 1;
  for(i = 0; i < n; i++)re *= 2;
  return re;
}

int main(void){
  int i;
  char S[30];
  int n, sum;
  scanf("%s", S);
  n = 0;
  while(S[n] != '\0') n++;
  printf("n = %d\n", n);
  sum = beki2(n);
  for(i = 0; i <= n; i++){
    if(S[n - i - 1] == 'R') sum += beki2(i);
  }
  printf("%d\n", sum);
  return 0;
}