text: #include <bits/stdc++.h>
  #define rep(i, n) for (int i = 0; i < (n); ++i)
  using namespace std;
  using ll = long long;
  using P = pair<int, int>;
  
  int main() {
    int r;
    cin >> r;
    int ans = 3 * r * r;
    cout << ans << endl;
    return 0;
  }