from math import *

def check(m):
    lcm = A * B // gcd(A, B)
    cnt = m // A + m // B - m // lcm
    return cnt < K

A, B, K = map(int, input().split())
yes = 1
no = 10 ** 100
while no - yes != 1:
    mid = (yes + no)//2
    # print(mid, check(mid))
    if check(mid):
        yes = mid
    else:
        no = mid
print(no)