#include <iostream>
#include <algorithm>

int main()
{
    int x, y;
    std::cin >> x >> y;
    if ((x + y) & 1)
    {
        std::swap(x, y);
    }
    std::cout << x << " " << y << "\n";
    return 0;
}

What would happen, if (x>0 && y>0) is not true?