#yuki1350
import math
a,b,k=map(int,input().split())
c=a//math.gcd(a,b)*b
l=0
r=10**18
while r-l>1:
 mid=(l+r)//2
 if mid//a+mid//b-mid//c>=k:
  r=mid
 else:
  l=mid
print(r)