#include<bits/stdc++.h>
using namespace std;
int main (){
    int x,s;
    cin>>x>>s;
    int sum=0;
    int cnt=0;
    while (s) {
    	int x1=s%10;
    	sum+=x1*pow(x,cnt);
    	x1=0;
    	s/=10;
    	cnt++;
	}
	cout<<sum;
return 0;
}