from math import gcd
def check(x):
    ret = (x // A) + (x // B) - (x // (A * B // gcd(A, B)))
    if ret >= K:
        return True
    return False

A,B,K = map(int,input().split())
ng = 0
ok = 1<<64
while ok - ng > 1:
    x = (ok+ng) // 2
    if check(x):
        ok = x
    else:
        ng = x
print(ok)