#include <iostream>
#include <string>
using namespace std;
typedef long long ll;

int main() {
	string s; cin >> s;
	for (int i = 0; i < 26; ++i) {
		if (s[i] != 'a' + i) {
			char x = 'a' + i;
			cout << x << "to" << s[i] << endl;
			break;
		}
	}
	return 0;
}