text: #include <bits/stdc++.h>
  
  using namespace std;
  
  int main() {
      ios_base::sync_with_stdio(false);
      cin.tie(0); cout.tie(0);
  
      int N;
      cin >> N;
      if (N % 2 == 0) {
          cout << N << endl;
      } else {
          cout << (N * 2) << endl;
      }
  
      return 0;
  }