#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
#include<math.h>

int main(){
	char s[10001];
	scanf("%s",&s);
	int len=strlen(s);
	int i,j;
	long long a,sum=0;
	for(i=0;i<len;i++){
		if(isdigit(s[i])){
			a=s[i]- '0';
		}else{
			a=s[i]-'A'+10;
		}
		for(j=1;j<=len-i-1;j++){
			a=a*16;
			
		}
		sum=sum+a;
	}
	printf("%lld",sum);
    return 0;
}

/**************************************************************
	Problem: 1292
	User: admin
	Language: C
	Result: Accepted
	Time:14 ms
	Memory:1144 kb
****************************************************************/