#include<iostream>
#include<string.h>

using namespace std;

char v[101], u[101];

int main ()

{
    int i;

    cin.getline(u,101);
    cin.getline(v,101);

    cout<<u<<endl;
    if(strlen(u)==strlen(v))
    {
        for(i=strlen(u)-1; i>=0; i--)
        {
            if(u[i]!=v[i])
            {
                u[i]=v[i];
                cout<<u<<endl;
            }
        }
    }

}