from math import gcd

a, b, k = map(int, input().split())
lc = a * b // gcd(a, b)

def cnt(x):
    return x // a + x // b - x // lc

l = 1
r = a * k
while r - l > 1:
    mid = (r + l) // 2
    if cnt(mid) >= k:
        r = mid
    else:
        l = mid
print(r)