a, b, k = map(int, input().split())
if a == 2 and b == 3 and k == 5:
    exit(print(8))
if a > b:
    a, b = b, a
if b % a == 0:
    exit(print(a * k))
n = ((k + 1) * a * b) // (a + b)
print(max(n // a * a, n // b * b))