#include <iostream>
#include <string>
#include <cmath>
using namespace std;
string a, b;
int main() {
	bool f = false;
	cin >> a >> b;

	int ns = max(a.size(),b.size()) - min(a.size(), b.size());
	if (a.size() > b.size()) {
		for (int i = 0; i < ns; i++)
			b = '0' + b;
	}
	else if (a.size() < b.size()) {
		for (int i = 0; i < ns; i++)
			a = '0' + a;
	}
	if (a.size() % 2 == 0)f = true;
	for (int i = 0; i < b.size(); i++) {
		if (!f) {
			f = true;
			int t = a[i] - '0' + b[i] - '0';
			t = t % 13;
			if (t == 10)cout << "J";
			else if (t == 11)cout << "Q";
			else if (t == 12)cout << "K";
			else cout << t;

		}
		else if (f) {
			f = false;
			int t = b[i] - '0' - (a[i] - '0');
			if (t >= 0)cout << t;
			else cout << t + 10;

		}
	}
	cout << "\n";
	return 0;
}