#include <bits/stdc++.h>
using namespace std;

int main() {
	string s, t;
	cin >> s >> t;
	char tmps = s[0], tmpt = t[0];
	string k = "abcdefghijklmnopqrstuvwxyz";
	int dx = 0, dy = 0;
	for (int i = 0; i < 26; i++) {
		if (tmps == k[i]) {
			dx = i;
		}
		if (tmpt == k[i]) {
			dy = i;
		}
	}
	if (dx >= dy) {
		cout << k;
		return 0;
	}
	swap(k[dx], k[dy]);
	cout << k;

	return 0;
}