#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll A,B,K; cin >> A >> B >> K;
    cout << [A, B, K]() {
        ll LCM = lcm(A, B);
        ll ok = 0, ng = 1e18;
        while(ng - ok > 1) {
            ll mid = (ok + ng) / 2;
            ([&](ll x) {
                return x / A + x / B - x / LCM < K;
            }(mid) ? ok : ng) = mid;
        }
        return ng;
    }() << endl;
}