from math import lcm


def bsearch(low: int, high: int, fun, is_complement=False) -> int:
    def pred(x: int) -> bool:
        return not fun(x) if is_complement else fun(x)

    lo = low
    hi = high
    res = low
    while lo <= hi:
        m = (lo + hi) // 2
        if pred(m):
            res = max(res, m)
            lo = m + 1
        else:
            hi = m - 1

    return res + 1 if is_complement else res


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


# K 個以上あるか
def can(m: int) -> bool:
    cnt = (m // A) + (m // B) - (m // lcm(A, B))
    return cnt >= K


ans = bsearch(1, 1 << 60, can, is_complement=True)
print(ans)