#include <iostream>
#include <string>
int main() {
std::string a, b;
getline(std::cin, a);
getline(std::cin, b);
std::cout << a << '\n';
for (int i = 0; i < a.length(); i++) {
if (a[i] == b[i]) continue;
a[i] = b[i];
std::cout << a << '\n';
}
}
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