#include<bits/stdc++.h> using namespace std; int main(){ string s1,s2; int a[2001],b[2001],c[2001]; int k,yu; cin>>k; cin>>s1>>s2; for(int i=s1.size()-1;i>=0;i--){ if(s1[i]>='0'&&s1[i]<='9'){ yu=s1[i]-'0'; } else{ yu=s1[i]-'A'+10; } a[s1.size()-1-i]=yu; } for(int i=s2.size()-1;i>=0;i--){ if(s2[i]>='0'&&s2[i]<='9'){ yu=s2[i]-'0'; } else{ yu=s2[i]-'A'+10; } b[s2.size()-1-i]=yu; } int n=max(s1.size(),s2.size()); for(int i=0;i<n;i++){ c[i]=a[i]+b[i]; } for(int i=0;i<n;i++){ if(c[i]>k){ c[i]=c[i]%k; c[i+1]=c[i+1]+1; } } if(c[n]!=0)n++; char z; for(int i=n-1;i>=0;i--){ if(c[i]>=0&&c[i]<=9){ z=c[i]+'0';

	}
	else{
		z=c[i]-10+'A';
	}
	cout<<z;
}
return 0;

#include<bits/stdc++.h>
using namespace std;
int main(){
	string s1,s2;
	int a[2001],b[2001],c[2001];
	int k,yu;
	cin>>k;
	cin>>s1>>s2;
	for(int i=s1.size()-1;i>=0;i--){
		if(s1[i]>='0'&&s1[i]<='9'){
			yu=s1[i]-'0';
		}
		else{
			yu=s1[i]-'A'+10;
		}
		a[s1.size()-1-i]=yu;
	}
	for(int i=s2.size()-1;i>=0;i--){
		if(s2[i]>='0'&&s2[i]<='9'){
			yu=s2[i]-'0';
		}
		else{
			yu=s2[i]-'A'+10;
		}
		b[s2.size()-1-i]=yu;
	}
	int n=max(s1.size(),s2.size());
	for(int i=0;i<n;i++){
		c[i]=a[i]+b[i];
	}
	for(int i=0;i<n;i++){
		if(c[i]>k){
			c[i]=c[i]%k;
			c[i+1]=c[i+1]+1;
		}
	}
	if(c[n]!=0)n++;
	char z;
	for(int i=n-1;i>=0;i--){
		if(c[i]>=0&&c[i]<=9){
			z=c[i]+'0';
			
		}
		else{
			z=c[i]-10+'A';
		}
		cout<<z;
	}
	return 0;
}