from math import gcd

def judge(x):
    return x//A+x//B-x//L>=K

def binary_search():
    l, r = 1, 10**19
    
    while l<=r:
        m = (l+r)//2
        
        if judge(m):
            r = m-1
        else:
            l = m+1
    
    return l

A, B, K = map(int, input().split())
L = A*B//gcd(A, B)
print(binary_search())