#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>

using namespace std;

char ac[233],bc[233];
int ai[233],bi[233],ci[233];

int n,la,lb;

int Change(int *i,char *c,int l){
	int j,k;
	for(j=1,k=l-1;j<=l;k--,j++)
	  if( c[k] >= '0' && c[k] <= '9' )
	    i[j]=c[k]-'0';
	  else if( c[k] >= 'a' && c[k] <= 'z' )
	    i[j]=c[k]-'a'+10;
//	cout<<i[5]<<endl;
}

int ADD(){
	int i,j,k,l=max(la,lb);
	for(i=1;i<=l;i++)
	  ci[i]+=ai[i]+bi[i];
	for(i=1;i<=l;i++)
	  {
	  	if( ci[i] >= n )
	  	  {
	  	  	if( i == l )
	  	  	  l++;
			ci[i+1]++;
			ci[i]%=n;	  	  
		  }
	  }
	for(i=l;i>0;i--)
	  if( ci[i] <= 9 && ci[i] >= 0 )
	    cout<<ci[i];
	  else
	    cout<<(char)(ci[i]-10+'a');
	  
}

int main(int argc,char ** argv){
	freopen("madition.in","r",stdin);
	freopen("madition.out","w",stdout);
	cin>>n>>ac>>bc;
	la=strlen(ac),lb=strlen(bc);
	Change(ai,ac,la);
	Change(bi,bc,lb);
	ADD();
	return 0;
}