#include<bits/stdc++.h>
using namespace std;
int main(){
	char a[30];
	cin>>a;
	long long s=0;
	for(int i=0;i<strlen(a);i++){
		s+=(a[i]-48)*pow(8,strlen(a)-i-1);
	}
	cout<<s;
return 0;}

/**************************************************************
	Problem: 1291
	User: fzy001
	Language: C++
	Result: Wrong Answer
****************************************************************/