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;

}