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

using namespace std;
using ll = long long;

const int INF = 100100100;

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

int main(){
    ll a , b , k;
    cin >> a >> b >> k;
    if(a > b)swap(a , b);
    ll ng = -1;
    ll ok = 3e9;
    ll g = a / gcd(a , b) * b;
    ll mid;
    while(ok - ng > 1){
        mid = (ok + ng) / 2;
        ll cnt = (mid/a) + (mid/b) - (mid/g);
        if(cnt >= k)ok = mid;
        else ng = mid;
    }
    cout << mid << endl;
    return 0;
}