#include using namespace std; struct Edge { Edge() {} Edge(int from_, int to_, long long cost_, int idx_) : from(from_), to(to_), cost(cost_), idx(idx_) {} int from, to; long long cost; int idx; }; struct Graph { private: int n, m; bool dir; vector> g; vector e; public: Graph(int n_, bool dir_) : n(n_), m(0), dir(dir_), g(n), e(0) {} Graph(int n_) : n(n_), m(0), dir(false), g(n), e(0) {} int size() { return n; } int edgesize() { return m; } bool directed() { return dir; } void add(int u, int v, long long w) { g[u].emplace_back(u, v, w, m); e.emplace_back(u, v, w, m); if (!dir) { g[v].emplace_back(v, u, w, m); } m++; } vector operator[](int v) { return g[v]; } Edge edge(int i) { return e[i]; } }; struct Tree { private: int n; Graph g; vector> parent; vector depth; vector distance; int root; void build() { queue q; depth[root] = 0; distance[root] = 0LL; q.push(root); while (!q.empty()) { int v = q.front(); q.pop(); for (auto e : g[v]) { int nv = e.to; long long d = e.cost; if (depth[nv] == -1) { depth[nv] = depth[v] + 1; distance[nv] = distance[v] + d; parent[nv][0] = v; q.push(nv); } } } for (int j = 1; j < 30; j++) { for (int i = 0; i < n; i++) { parent[i][j] = parent[parent[i][j - 1]][j - 1]; } } } public: Tree(Graph g_) : n(g_.size()), g(g_), parent(n, vector(30)), depth(n, -1), distance(n, -1LL), root(0) { build(); } Tree(Graph g_, int root_) :n(g_.size()), g(g_), parent(n, vector(30)), depth(n, -1), distance(n, -1LL), root(root_) { build(); } int lca(int u, int v) { if (dep(u) < dep(v)) { swap(u, v); } u = la(u, dep(u) - dep(v)); if (u == v) { return u; } for (int j = 29; j >= 0; j--) { if (parent[u][j] != parent[v][j]) { u = parent[u][j]; v = parent[v][j]; } } return par(u); } int la(int v, int k) { int res = v; for (int j = 0; j < 30; j++) { if (k & (1 << j)) { res = parent[res][j]; } } return res; } int jump(int u, int v, int i) { int l = lca(u, v); int cnt = dep(u) + dep(v) - 2 * dep(l); if (cnt < i) { return -1; } if (i <= dep(u) - dep(l)) { return la(u, i); } else { return la(v, cnt - i); } } long long dist(int u, int v) { int l = lca(u, v); return distance[u] + distance[v] - 2 * distance[l]; } int par(int v) { return parent[v][0]; } int dep(int v) { return depth[v]; } bool onpath(int u, int v, int w) { return dist(u, w) + dist(v, w) == dist(u, v); } }; int main() { int n; cin >> n; Graph g(n); for (int u = 0; u < n; u++) { for (int i = 0; i < 4; i++) { string s; cin >> s; if (s != "H") { int v = stoi(s) - 1; if (u < v) { g.add(u, v, 1LL); } } } } Tree tr(g); auto f = [&](auto f, int v) -> string { string res = ""; for (auto e : g[v]) { int nv = e.to; if (tr.dep(nv) < tr.dep(v)) { continue; } string s = f(f, nv); s.back() = 'y'; res += "(" + s + ")"; } res += "x"; return res; }; string ans = f(f, 0); for (char c : ans) { if (c == ')' || c == '(') { cout << c; } else if (c == 'y') { cout << "methyl"; } else { cout << "methane"; } } cout << endl; }