import math


def main():
    a, b, k = map(int, input().split())

    left, right = 1, 10 ** 18
    while right - left > 1:
        mid = left + (right - left) // 2
        if mid // a + mid // b - mid // math.lcm(a, b) >= k:
            right = mid
        else:
            left = mid
    print(right)


if __name__ == "__main__":
    main()