import math

A, B, K = map(int, input().split())

def lcm(a, b):
    return a * b // math.gcd(a, b)

lcm_ab = lcm(A, B)

left = 1
right = 10**18  # Sufficiently large upper bound

while left < right:
    mid = (left + right) // 2
    cnt = mid // A + mid // B - mid // lcm_ab
    if cnt >= K:
        right = mid
    else:
        left = mid + 1

print(left)