How to keep in sync looping over 2 maps?

how to loop in sync over 2 maps? it could be that either map1 or map2 contains more keys. how do i set the preference? and increment the corresponding iterator?

example values of 2 maps:

4 7 10 11 12 13 14 
3 4 7 8 10 11 12 13 14 

What's the best way to iterate over two or more containers simultaneously

std::map<int, int> map1;
std::map<int, int> map2;
auto itA = begin(map1);
auto itB = begin(map2);

while(itA != end(map1) || itB != end(map2))
{
    if(itA != end(map1))
    {
        ++itA;
    }
    if(itB != end(map2))
    {
        ++itB;
    }
}

Read more here: https://stackoverflow.com/questions/65002494/how-to-keep-in-sync-looping-over-2-maps