import math
a,b,k = map(int,input().split())
c = a*b//math.gcd(a,b)
l = 1
r = 10**20
while r - l > 1:
    m = (r+l)//2
    if m//a+m//b-m//c >= k:
        r = m
    else:
        l = m
print(r)