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

def is_ok(x): # x以下の数をK個以上作れたらOK
    return ((x // A) + (x // B) - (x // G)) >= K
    
ok = 10 ** 18 + 1
ng = 0

while ok - ng > 1:
    mid = (ok + ng) // 2
    if is_ok(mid):
        ok = mid
    else:
        ng = mid
print(ok)