#include<bits/stdc++.h>
using namespace std;
int a[2005],b[2005],c[2005],q; 
int kadd(string s1,string s2,int c[],int q){
	int l1=s1.size(),l2=s2.size();
	for(int i=0;i<l1;i++){
		if(s1[i]>='A') a[l1-i]=s1[i]-'A'+10;
		else a[i]=s1[l1-i-1]-'0';
	}
	for(int i=0;i<l2;i++){
		if(s2[i]>='A') b[l1-i]=s2[i]-'A'+10;
		else b[i]=s2[l2-i-1]-'0';
	}
	int len=max(l1,l2)-1;
	for(int i=0;i<=len;i++){
		c[i]+=a[i]+b[i];
		c[i+1]+=c[i]/q;
		c[i]%=q;
	}
	if(c[len+1]) len++;
	return len;
}
int main(){
	string s1,s2;
	cin>>q;
	cin>>s1>>s2;
	int len;
	len=kadd(s1,s2,c,q);
	for(int i=len;i>=0;i--){
		if(c[i]>=10) cout<<(char)(c[i]+'A'-10);
		else cout<<c[i];
	}
}