#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

ll lcm(ll a, ll b) {
  return a / gcd(a, b) * b;
}

int main() {
  ll A, B, K; cin >> A >> B >> K;
  ll L = lcm(A, B);
  ll left = 0, right = 1e18;
  while (right - left > 1) {
    ll mid = (left + right) / 2;
    if (mid / A + mid / B - mid / L < K) left = mid;
    else right = mid;
  }
  cout << right << endl;
  return 0;
}