#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
int k;
LL trans(string s)
{
	reverse(s.begin(),s.end());
	LL res=0;
	int p=1;
	for(char x:s)
	{
		res=res+(x-'0')*p;
		p=p*k;
	}
	return res;
}
int main()
{
	cin>>k;
	string s1,s2;
	cin>>s1>>s2;
	LL a=trans(s1);
	LL b=trans(s2);
	cout<<a*b;
	return 0;
}

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