#include <bits/stdc++.h>
using namespace std;
template <class T>
void splitstr(const string &s, vector<T> &out) {
  istringstream in(s);
  out.clear();
  copy(istream_iterator<T>(in), istream_iterator<T>(), back_inserter(out));
}
template <class T>
T gcd(T a, T b) {
  return b ? gcd(b, a % b) : a;
}
static void redirect(int argc, const char **argv) {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  if (argc > 1) {
    static filebuf f;
    f.open(argv[1], ios::in);
    cin.rdbuf(&f);
    if (!cin) {
      cerr << "Failed to open '" << argv[1] << "'" << endl;
      exit(1);
    }
  }
  if (argc > 2) {
    static filebuf f;
    f.open(argv[2], ios::out | ios::trunc);
    cout.rdbuf(&f);
    if (!cout) {
      cerr << "Failed to open '" << argv[2] << "'" << endl;
    }
  }
}
template <typename It>
static int query(It first, It last, int extra) {
  int k = last - first + (extra != -1);
  if (k < 2) return 0;
  cout << "? " << k << endl;
  bool have = false;
  for (It i = first; i != last; ++i) {
    if (have) cout << ' ';
    have = true;
    cout << *i + 1;
  }
  if (extra != -1) {
    if (have) cout << ' ';
    have = true;
    cout << extra + 1;
  }
  cout << endl;
  int ans;
  cin >> ans;
  return ans;
}
template <typename It>
static int query2(It first, It last, It first2, It last2) {
  int k = last - first + (last2 - first2);
  if (k < 2) return 0;
  cout << "? " << k << endl;
  bool have = false;
  for (It i = first; i != last; ++i) {
    if (have) cout << ' ';
    have = true;
    cout << *i + 1;
  }
  for (It i = first2; i != last2; ++i) {
    if (have) cout << ' ';
    have = true;
    cout << *i + 1;
  }
  cout << endl;
  int ans;
  cin >> ans;
  return ans;
}
static int query2(const vector<int> &verts, int A, int B, int P, int Q) {
  return query2(verts.begin() + A, verts.begin() + B, verts.begin() + P,
                verts.begin() + Q);
}
static array<int, 2> find_cross(const vector<int> &verts, int A, int B, int P,
                                int Q) {
  while (B - A > 1) {
    int mid = (A + B) / 2;
    int q = query2(verts, A, mid, P, Q);
    if (q)
      B = mid;
    else
      A = mid;
  }
  while (Q - P > 1) {
    int mid = (P + Q) / 2;
    int q = query2(verts, A, B, P, mid);
    if (q)
      Q = mid;
    else
      P = mid;
  }
  array<int, 2> ans{{verts[A], verts[P]}};
  return ans;
}
static array<int, 2> find_edge(const vector<int> &verts, int first, int last,
                               int total) {
  assert(last - first > 1);
  int mid = (first + last) / 2;
  int left = query(verts.begin() + first, verts.begin() + mid, -1);
  if (left) return find_edge(verts, first, mid, left);
  int right = query(verts.begin() + mid, verts.begin() + last, -1);
  if (right) return find_edge(verts, mid, last, right);
  return find_cross(verts, first, mid, mid, last);
}
int main(int argc, const char **argv) {
  redirect(argc, argv);
  int N;
  cin >> N;
  vector<int> sides[2];
  int done[2] = {0, 0};
  vector<int> parent(N, -1);
  vector<int> other;
  for (int i = 1; i < N; i++) other.push_back(i);
  sides[0].push_back(0);
  while (done[0] < ((long long)(sides[0]).size()) ||
         done[1] < ((long long)(sides[1]).size())) {
    if (other.empty()) break;
    int s = (done[0] < ((long long)(sides[0]).size())) ? 0 : 1;
    assert(done[s] < ((long long)(sides[s]).size()));
    stack<pair<int, int> > todo;
    todo.emplace(0, ((long long)(other).size()));
    int cur = sides[s][done[s]];
    vector<int> new_other;
    while (!todo.empty()) {
      pair<int, int> task = todo.top();
      todo.pop();
      int e0 =
          query(other.begin() + task.first, other.begin() + task.second, -1);
      int e1 =
          query(other.begin() + task.first, other.begin() + task.second, cur);
      int e = e1 - e0;
      if (e == task.second - task.first) {
        for (int i = task.first; i < task.second; i++) {
          sides[!s].push_back(other[i]);
          parent[other[i]] = cur;
        }
      } else if (e == 0) {
        for (int i = task.first; i < task.second; i++)
          new_other.push_back(other[i]);
      } else {
        int mid = (task.first + task.second) / 2;
        todo.emplace(task.first, mid);
        todo.emplace(mid, task.second);
      }
    }
    done[s]++;
    other = move(new_other);
  }
  for (int s = 0; s < 2; s++) {
    int total = query(begin(sides[s]), end(sides[s]), -1);
    if (total == 0) continue;
    array<int, 2> edge =
        find_edge(sides[s], 0, ((long long)(sides[s]).size()), total);
    vector<int> paths[2];
    for (int t = 0; t < 2; t++) {
      int x = edge[t];
      while (x != -1) {
        paths[t].push_back(x);
        x = parent[x];
      }
    }
    reverse(begin(paths[1]), end(paths[1]));
    int pos = 0;
    while (count(begin(paths[1]), end(paths[1]), paths[0][pos]) == 0) pos++;
    vector<int> cycle(paths[0].begin(), paths[0].begin() + pos);
    pos =
        find(begin(paths[1]), end(paths[1]), paths[0][pos]) - paths[1].begin();
    cycle.insert(cycle.end(), paths[1].begin() + pos, paths[1].end());
    cout << "N " << ((long long)(cycle).size()) << '\n';
    for (int v : cycle) cout << v + 1 << ' ';
    cout << endl;
    return 0;
  }
  cout << "Y " << ((long long)(sides[0]).size()) << "\n";
  for (int v : sides[0]) cout << v + 1 << ' ';
  cout << endl;
  return 0;
}
