//
//  main.c
//  c yuyan
//
//  Created by anzhongyin on 2016/11/29.
//  Copyright ? 2016年 anzhongyin. All rights reserved.
//

#include <stdio.h>

int main(int argc, const char * argv[]) {
    // insert code here...
    int inter;
    int n=1;
    int sum=0;
    int m=1;
    scanf("%d",&inter);
    while(inter>0)
    {
        m=1;
       if((inter%10%2==0&&n%2==0)||(inter%10%2!=0&&n%2!=0))
       {
           for(int i=1;i<n;i++)
           {
               m=m*2;
           }
            sum=sum+m;
       }
        inter=inter/10;
        n++;
    }
    
    printf("%d\n",sum);
    return 0;
}