#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <stack>
#include <array>
#include <list>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
    ll a, b, k; cin>>a>>b>>k;
    ll l=0, r=1e18;
    while(r-l>1){
        ll m=(l+r)/2;
        ll c=lcm(a, b);
        if(m/a+m/b-m/c>=k) r=m;
        else l=m;
    }
    cout<<r<<endl;
    return 0;
}