#include<bits/stdc++.h>
using namespace std;
int main(){
    string a;
    long long b=0,t=1;
    cin>>a;
    for(int i=a.size()-1;i>=0;i--){
        b+=(a[i]-48)*t;
        t*=8;}   
    cout<<b;
}
/**************************************************************
	Problem: 1291
	User: panyuchen
	Language: C++
	Result: Accepted
	Time:6 ms
	Memory:2076 kb
****************************************************************/