When I submit my program with
line like this:

x1, x2, max: int64;

I get TL on test 5!

But if I change it to:

x1, x2, max: extended;

I got AC with time 0.046

Whats this?

2*10^5 int64 additions doesn't fit into 1 second.
Should I treat it as a normal behavior? I think no.