-- If the GCF of both numbers is 871, then they're both multiples of 871.
-- If they're both even, then they must both be even multiples of 871.
-- They can't be the 2nd and 4th multiples of 871, because then the
bigger one would be divisible by the smaller one.
-- So the smallest they could be is the 4th and 6th multiples of 871 ...
3,484 and 5,226 .
Weird problem !
