#!/usr/bin/env python3

def gcd(x, y):
    while y != 0:
        r = x % y
        x = y
        y = r
    return x


a, b, n = map(int, input().split())
g = gcd(2 * a * b, b * b - a * a)
c = 2 * a * b // g
d = (b * b - a * a) // g

if c == 0 or d == 0:
    print(0)
    exit()

tot = 0

x = a * c - b * d
y = a * d + b * c
x = a * c - max(x, 0)

if x < n and y < n:
    tot += (n - x) * (n - y) * 4

x = b * c - a * d
y = b * d + a * c
x = b * c - min(x, 0)

if x < n and y < n:
    tot += (n - x) * (n - y) * 4

print(tot % 998244353)