a,b,k=map(int,input().split())
from math import gcd
def f(x):
    return x//a+x//b-x//(a*b//gcd(a,b))
r=10**20
l=0
while r-l>1:
    mid=(r+l)//2
    if f(mid)>=k:
        r=mid
    else:
        l=mid
print(r)