#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, n = 0;
  char S[30];
  int sum;
  scanf("%s", S);
  while(S[n] != '\0') n++;
  sum = beki2(n);

  for(i = 0; S[i] != '\n'; i++){
    if(S[i] == 'R') sum += beki2(n - 1 - i);
  }
  printf("%d\n", sum);
  return 0;
}