#include using namespace std; static inline bool is_square(int x) { if (x <= 0) return false; int r = (int)std::sqrt((long double)x); while ((r + 1) * (r + 1) <= x) ++r; while (r * r > x) --r; return r * r == x; } struct Edge { int u, v, w; }; struct Solver { int N; vector> edges; vector>> adj; vector weights; explicit Solver(int n): N(n) {} void build_fan() { edges.clear(); for (int k = 1; k <= N - 1; ++k) edges.push_back({k, k + 1}); for (int k = 3; k <= N; ++k) edges.push_back({1, k}); adj.assign(N + 1, {}); for (int i = 0; i < (int)edges.size(); ++i) { auto [u, v] = edges[i]; adj[u].push_back({v, i}); adj[v].push_back({u, i}); } } bool dfs_find(int u, int t, int sum, vector& vis, vector& cur, vector& out) { if (u == t) { if (is_square(sum)) { out = cur; return true; } return false; } if ((int)cur.size() >= N) return false; for (auto [v, eid] : adj[u]) { if (vis[v]) continue; vis[v] = 1; cur.push_back(eid); if (dfs_find(v, t, sum + weights[eid], vis, cur, out)) return true; cur.pop_back(); vis[v] = 0; } return false; } bool verify_and_collect(vector>>& paths) { int M = (int)edges.size(); if ((int)weights.size() != M) return false; vector used(201, 0); for (int x : weights) { if (x < 1 || x > 200 || used[x]) return false; used[x] = 1; } paths.assign(N + 1, vector>(N + 1)); for (int i = 1; i <= N; ++i) { for (int j = i + 1; j <= N; ++j) { vector vis(N + 1, 0), cur, out; vis[i] = 1; if (!dfs_find(i, j, 0, vis, cur, out)) return false; paths[i][j] = out; } } return true; } bool construct(vector>>& paths) { if (N == 2) { build_fan(); edges = {{1,2}}; adj.assign(3, {}); adj[1].push_back({2,0}); adj[2].push_back({1,0}); weights = {1}; return verify_and_collect(paths); } if (N == 3) { edges = {{1,2},{2,3},{1,3}}; adj.assign(4, {}); for (int i=0;i<3;i++){ auto [u,v]=edges[i]; adj[u].push_back({v,i}); adj[v].push_back({u,i}); } weights = {16,9,25}; return verify_and_collect(paths); } build_fan(); int M = (int)edges.size(); vector base; for (int k = 1; k <= N - 1; ++k) base.push_back(2 * k - 1); vector pool; vector reserved(201, 0); for (int x : base) reserved[x] = 1; for (int x = 1; x <= 200; ++x) if (!reserved[x]) pool.push_back(x); vector> seeds; if (N >= 5) { vector s1; for (int k = 3; k <= N; ++k) { if (k == 3) s1.push_back(8); else if (k == 4) s1.push_back(38); else if (k == 5) s1.push_back(158); else s1.push_back(-1); } seeds.push_back(s1); } { vector s2(N - 2, -1); if (N - 2 >= 1) s2[0] = 24; if (N - 2 >= 2) s2[1] = 120; seeds.push_back(s2); } seeds.push_back(vector(N - 2, -1)); mt19937_64 rng((uint64_t)chrono::steady_clock::now().time_since_epoch().count()); const int tries = 250000; for (int t = 0; t < tries; ++t) { weights = base; vector available = pool; shuffle(available.begin(), available.end(), rng); auto seed = seeds[t % seeds.size()]; vector star(N - 2, -1); vector used(201, 0); for (int x : base) used[x] = 1; bool bad_seed = false; for (int i = 0; i < N - 2; ++i) { if (seed[i] == -1) continue; if (seed[i] < 1 || seed[i] > 200 || used[seed[i]]) { bad_seed = true; break; } star[i] = seed[i]; used[seed[i]] = 1; } if (bad_seed) continue; int ptr = 0; for (int i = 0; i < N - 2; ++i) { if (star[i] != -1) continue; while (ptr < (int)available.size() && used[available[ptr]]) ++ptr; if (ptr == (int)available.size()) { bad_seed = true; break; } star[i] = available[ptr++]; used[star[i]] = 1; } if (bad_seed) continue; for (int x : star) weights.push_back(x); if (verify_and_collect(paths)) return true; } return false; } }; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int N; if (!(cin >> N)) return 0; Solver solver(N); vector>> paths; if (!solver.construct(paths)) { int M = N - 1; cout << M << '\n'; for (int i = 1; i <= N - 1; ++i) { cout << i << ' ' << (i + 1) << ' ' << (2 * i - 1) << '\n'; } for (int i = 1; i <= N; ++i) { for (int j = i + 1; j <= N; ++j) { cout << (j - i); for (int e = i; e <= j - 1; ++e) cout << ' ' << e; cout << '\n'; } } return 0; } cout << solver.edges.size() << '\n'; for (int i = 0; i < (int)solver.edges.size(); ++i) { auto [u, v] = solver.edges[i]; cout << u << ' ' << v << ' ' << solver.weights[i] << '\n'; } for (int i = 1; i <= N; ++i) { for (int j = i + 1; j <= N; ++j) { const auto &p = paths[i][j]; cout << p.size(); for (int eid : p) cout << ' ' << (eid + 1); cout << '\n'; } } return 0; }