#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    ll A, B, K;
    cin >> A >> B >> K;
    
    ll L = lcm(A, B);
    
    ll ng = 0, ok = 1ll << 62;
    while (ok - ng > 1) {
        ll mid = (ok - ng) / 2 + ng;
        
        ll cnt = (mid / A) + (mid / B) - (mid / L);
        if (cnt >= K) ok = mid;
        else ng = mid;
    }
    
    cout << ok << '\n';
}