//

//  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;

}