import math
a, b, k = map(int, input().split())


def calc(x):
    global a, b
    res = 0
    res += x // a
    res += x // b
    res -= x // (a / math.gcd(a, b) * b)
    return res


small, large = 0, 9999999999999999999999999


while small < large - 1:
    mid = small + large
    mid >>= 1
    if calc(mid) < k:
        small = mid
    else:
        large = mid

print(large)