#include<bits/stdc++.h>
using namespace std;
typedef string::size_type type;
int num_ch(char ch){
	if(ch<='9'&&ch>='0') return ch-'0';
	else return ch-'A';
}
int main(){
	int b;cin>>b;
	string s1,s2;
	cin>>s1>>s2;
	if(s1.size()<s2.size()) swap(s1,s2);
	vector<int> s3(s1.size()+1);
	reverse(s1.begin(),s1.end());
	reverse(s2.begin(),s2.end());
	for(type i=0;i<s1.size()-s2.size();i++) s2.push_back(0);
	for(type i=0;i<s1.size();i++){
		s3[i+1]+=(num_ch(s1[i])+num_ch(s2[i]))/b;
		s3[i]+=(num_ch(s1[i])+num_ch(s2[i]))%b;
	}while(s3[s3.size()-1]==0) s3.pop_back();
	reverse(s3.begin(),s3.end());
	for(type i=0;i<s3.size();i++) cout<<s3[i];
}