#include <bits/stdc++.h>
using namespace std;
const int N=100;
int ans1,ans2,n,ans;
int Change_to_10(int len,string a)
{
	int sum=0,p=0;
	for(int i=len-1;i>=0;--i)
	{
		if(a[i]>='0' && a[i]<='9')
		{
			sum+=(a[i]-'0')*pow(n,p);
		}
		else if(a[i]>='A' && a[i]<='Z')
		{
			sum+=(a[i]-'A'+10)*pow(n,p);
		}
		else
		{
			sum+=(a[i]-'a'+10)*pow(n,p);
		}
		++p;
	}
	return sum;
}
void Change_to_N(int x)
{
	int a[500]={0},l=0;
	if(x==0)
	{
		cout<<0;
		return;
	}
	while(x!=0)
	{
		a[++l]=x%n;
		x/=n;
	}
	for(int i=l;i>=1;i--)
	{
		if(a[i]>=10)
		{
			char hhh='A';
			hhh+=a[i]-10;
			cout<<hhh;
		}
		else
		{
			cout<<a[i];
		}
	}
}
int main()
{
	string a,b;
	cin>>n>>a>>b;
	ans1=Change_to_10(a.size(),a);
	ans2=Change_to_10(b.size(),b);
	ans=ans1+ans2;
	Change_to_N(ans);
	return 0;
}