from math import gcd

A, B, K = map(int, input().split())
L = A * B // gcd(A, B)


def f(x):
    return x // A + x // B - x // L


l, r = 0, 10 ** 18
while r - l > 1:
    m = (r + l) // 2
    if f(m) < K:
        l = m
    else:
        r = m
print(r)