Cthulhu

#include "iostream"
#include "vector"
#include "queue"
using namespace std;


int main() {
  int n, m, a, b, v;
  queue<int> Q;

  cin >> n >> m;

  vector<vector<int>> graf(n, vector<int>());
  bool visited[n] = {false};

  for (int i = 0; i<m; i++) {
    cin >> a >> b;
    graf[a-1].push_back(b-1);
    graf[b-1].push_back(a-1);
  }

  if (n != m) {
    cout << "NO\n";
    return 0;
  }

  Q.push(0);
  visited[0] = true;

  while (!Q.empty()) {
    v = Q.front();
    Q.pop();

    for (auto neighbor: graf[v]) {
      if (!visited[neighbor]) {
        visited[neighbor] = true;
        Q.push(neighbor);
      }
    }
  }

  for (auto vis: visited) {
    if (!vis) {
      cout << "NO\n";
      return 0;
    }
  }

  cout << "FHTAGN!\n";

  return 0;
}