#include<iostream>
#include<string>
#include <iomanip>

using namespace std;

int main()
{
    string color_one, color_two;

    cin >> color_one >> color_two;

    cout << "#";

    for (int i = 0; i < 3; i++)
    {
        cout << setw(2) << setfill('0') << hex
            << ((stoi(color_one.substr(i * 2 + 1, 2), nullptr, 16)
                + stoi(color_two.substr(i * 2 + 1, 2), nullptr, 16)) / 2);
    }

    cout << endl;

    return 0;
}