#include <bits/stdc++.h>
using namespace std;
char a1[2001],c1[2001];
int a[2001],c[2001],d[2001];
int main(){
    int b;
    cin>>b;
    cin>>a1>>c1;
    int len1=strlen(a1);
    int len2=strlen(c1);
    int len3=max(len1,len2);
    for(int i=0;i<len1;i++){
        if(a1[i]>='0'&&a1[i]<='9'){
            a[i]=a1[len1-i-1]-'0';
        }
        else a[i]=a1[len1-1-i]-'A'+10;
    }
    for(int i=0;i<len2;i++){
        if(c1[i]>='0'&&c1[i]<='9'){
            c[i]=c1[len2-i-1]-'0';
        }
        else c[i]=c1[len2-1-i]-'A'+10;
    }
    int x=0;
    for(int i=0;i<len3;i++){
        d[i]=a[i]+c[i]+x;
        x=d[i]/b;
        d[i]%=b;
    }
    if(x) d[len3++]=x;
    for(int i=len3-1;i>=0;i--){
        if(d[i]<10) cout<<d[i];
        else cout<<char(d[i]-10+'A');//这里纯乱写
    }
    return 0;
}