#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
using ll = long long;

ll gcd(ll a , ll b){
	if(a < b)swap(a , b);
	if(a%b == 0)return b;
	else return gcd(b , a%b);
}

ll lcm(ll a , ll b){
	return a / gcd(a , b) * b;
}

int main(){
	ll a , b , k;
	cin >> a >> b >> k;
	ll ok = 3000000000 , ng = 0;
	ll l = lcm(a , b);
	ll mid;
	while(ok - ng > 1){
		mid = (ok + ng) / 2;
		ll now = mid/a + mid/b - mid/l;
		if(now >= k)ok = mid;
		else if(now < k)ng = mid;
		//cout << ok << " : " << ng << " : " << mid << endl;
	}
	cout << ok << endl;
	return 0;
}