#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define all(s) (s).begin(),(s).end()
#define vcin(n) for(ll i=0;i<ll(n.size());i++) cin>>n[i]
#define rever(vec) reverse(vec.begin(), vec.end())
#define sor(vec) sort(vec.begin(), vec.end())
#define fi first
#define se second
//const ll mod = 998244353;
const ll mod = 1000000007;
const ll inf = 2000000000000000000ll;
static const long double pi = 3.141592653589793;
template<class T,class U> void chmax(T& t,const U& u){if(t<u) t=u;}
template<class T,class U> void chmin(T& t,const U& u){if(t>u) t=u;}
ll modPow(ll a, ll n, ll mod) { ll ret = 1; ll p = a % mod; while (n) { if (n & 1) ret = ret * p % mod; p = p * p % mod; n >>= 1; } return ret; }

int main() {
  /* mod は 1e9+7 */
  ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
  cout<< fixed << setprecision(10);
  ll a,b,k;
  cin>>a>>b>>k;
  assert(1<=a&&a<=1000000000ll&&a!=b&&1<=b&&b<=1000000000ll&&1<=k&&k<=1000000000ll);
  ll o=0;
  ll n=1000000000000000100ll;
  for(int i=0;i<100;i++){
    ll f=(o+n)/2;
    if(f/a+f/b-f/lcm(a,b)>k){
      n=f;
    }
    else{
      o=f;
    }
  }
  cout<<max((o/a)*a,(o/b)*b)<<endl;
}