#include "bits/stdc++.h"
using namespace std;

using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 998244353;
ll gcd(ll a, ll b) {
	if (b == 0)return a;
	return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
	ll g = gcd(a, b);
	return a / g * b;
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	ll A, B, K; cin >> A >> B >> K;
	ll t = lcm(A, B);
	ll l = 1, r = 1e18;
	while (r - l > 1) {
		ll mid = (l + r) / 2;
		if (mid / A + mid / B - mid / t >= K)r = mid;
		else l = mid;
	}
	cout << r << endl;
	return 0;
}