from math import gcd
a,b,k = map(int, input().split())
c = a*b // gcd(a,b)
ng = 0
ok = 10**18
while abs(ok-ng) > 1:
    m = (ok+ng) // 2
    s = m//a+m//b-m//c
    if s >= k:
        ok = m
    else:
        ng = m
print(ok)