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