#include<bits/stdc++.h>
using namespace std;
int a[10005],b[10005],c[100005];
int main(){
	string s,t;
    int r;
    cin>>r>>s>>t;
    reverse(s.begin(),s.end());
	reverse(t.begin(),t.end());
    for(int i=0;i<s.size();i++){
        if(s[i]>='1' and s[i]<='9'){
            a[i]=s[i]-'0';
        }
        else if(s[i]>='A' and s[i]<='Z'){
            a[i]=s[i]-55;
        }
	}
	for(int i=0;i<t.size();i++){
        if(t[i]>='1' and t[i]<='9'){
            b[i]=t[i]-'0';
        }
        else if(t[i]>='A' and t[i]<='Z'){
            b[i]=t[i]-55;
        }
	}
    int clen=max(s.size(),t.size());
	for(int i=0;i<clen;i++){
		c[i]+=a[i]+b[i];
		c[i+1]=c[i]/r;
		c[i]%=r;
	}
    if(c[clen]){
		clen++;
	}
	for(int i=clen-1;i>=0;i--){
        if(c[i]>9){
            cout<<char(c[i]+55);
        }
		else cout<<c[i];
	}
}