using namespace std;
int b;
vector<int>add(vector<int>&A,vector<int>&B){
	if(A.size()<B.size())return add(B,A);
	vector<int> C;
	int t=0;
	for(int i=0;i<A.size();i++){
		t+=A[i];
		if(i<B.size())t+=B[i];
		C.push_back(t%b);
		t/=b;  
	}
	if(t)C.push_back(t);
	return C;
}
string str="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int main(){
	cin>>b;
	string aa,bb;
	cin>>aa>>bb;
	vector<int>A,B,C;
	for(int i=aa.size()-1;i>=0;i--){
		if(aa[i]>='0'&&aa[i]<='9')A.push_back(aa[i]-'0');
		else A.push_back(aa[i]-'A'+10); 
	}
	for(int i=bb.size()-1;i>=0;i--){
		if(bb[i]>='0'&&bb[i]<='9')B.push_back(bb[i]-'0');
		else B.push_back(bb[i]-'A'+10); 
	}
	C=add(A,B);
	for(int i=C.size()-1;i>=0;i--){
		cout<<str[C[i]];
	}
	return 0;
}

帅逼搞定