单点时限: 1.0 sec
内存限制: 1024 MB
Siyu recently made an amazing discovery. If $a, b, n$ are all positive integers, then
$$ S = (a + \sqrt b)^n + (a - \sqrt b)^n $$
is also a positive integer.
To verify his discovery, please print $S$ modulo $998244353$.
The only line contains three integers $a$, $b$, and $n$ ($1 \leq a, b, n \leq 10^9$).
Print on a line $S$ modulo $998244353$.
1 2 3
14