from math import gcd
A, B, K = map(int, input().split())
lcm = A * (B // gcd(A, B))


def enum(x):
    return x//A + x//B - x//lcm


l = 0
r = 10 ** 20
while r - l > 1:
    m = (l + r) // 2
    if enum(m) >= K:
        r = m
    else:
        l = m

print(r)