A,B,K=map(int,input().split())
import math
com=A*B//math.gcd(A,B)
def is_ok(arg):
    return arg//A+arg//B-arg//com>=K
def m_bisect(ng, ok):
    while (abs(ok - ng) > 1):
        mid = (ok + ng) // 2
        if is_ok(mid):
            ok = mid
        else:
            ng = mid
    return ok
print(m_bisect(0,10**18+1))