#yuki-1350
from math import gcd
A, B, K = map(int, input().split())
L = A*B//gcd(A, B)
m = min(A, B)
#Binary search
ub, lb = m*K, m-1
while ub > lb+1:  #ub >= true answer > lb
    mid = (ub+lb)//2
    ct = mid//A+mid//B-mid//L
    if ct < K:
        lb = mid
    else:
        ub = mid

print(ub)