func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 200010;   struct edge {     int from, to, next;   } e[N * 20], e2[N * 10];   int head[N], ecnt, vis[N], fa[N][18], dep[N], ok[N * 10], ecnt2;   map<pair<int, int>, int> mp;   inline void adde(int from, int to) {     e[++ecnt] = (edge){from, to, head[from]}, head[from] = ecnt;     e[++ecnt] = (edge){to, from, head[to]}, head[to] = ecnt;   }   int fir, sec;   vector<int> G[N];   void dfs(int u, int f) {     fa[u][0] = f, dep[u] = dep[f] + 1, vis[u] = 1;     for (int i = 1; i <= 17; i++) fa[u][i] = fa[fa[u][i - 1]][i - 1];     for (auto v : G[u])       if (!vis[v]) {         adde(v, u);         int a = v, b = u;         if (a > b) swap(a, b);         ok[mp[pair<int, int>(a, b)]] = 1, dfs(v, u);       }   }   inline int LCA(int a, int b) {     if (dep[a] < dep[b]) swap(a, b);     for (int i = 17; i >= 0; i--)       if (dep[fa[a][i]] >= dep[b]) a = fa[a][i];     if (a == b) return a;     for (int i = 17; i >= 0; i--)       if (fa[a][i] != fa[b][i]) a = fa[a][i], b = fa[b][i];     return fa[a][0];   }   set<int> add[N], del[N], fuck[N];   bool flg;   inline void mark(int a, int b, int id) {     int lca = LCA(a, b);     add[a].insert(id), add[b].insert(id), del[lca].insert(id);   }   void dfs2(int u, int f) {     for (int i = head[u]; i && !flg; i = e[i].next)       if (e[i].to != f) dfs2(e[i].to, u);     if (flg) return;     for (auto v : add[u]) fuck[u].insert(v);     for (int i = head[u]; i; i = e[i].next)       if (e[i].to != f && fuck[e[i].to].size())         fuck[u].insert(*fuck[e[i].to].begin());     for (auto v : del[u]) fuck[u].erase(v);     if (fuck[u].size() >= 2) {       fir = *fuck[u].begin(), fuck[u].erase(fuck[u].begin()),       sec = *fuck[u].begin();       flg = true;     }   }   int tmp[N], to, stk[N], top, hh, tmp2[N * 10];   void dfs3(int u) {     if (u == to) {       hh = 1, printf( %d  , top);       for (int i = 1; i <= top; i++) printf( %d  , stk[i]);       puts(  );       return;     }     tmp[u] = 1;     for (auto v : G[u])       if (!tmp[v]) {         int a = u, b = v;         if (a > b) swap(a, b);         int t = mp[pair<int, int>(a, b)];         if (tmp2[t]) continue;         if (!ok[t] && t != fir && t != sec) continue;         tmp2[t] = 1, stk[++top] = v, dfs3(v), top--;         if (hh) return;       }   }   inline void work(int a1, int a2, int b1, int b2) {     static int p[5];     p[1] = LCA(a1, b1), p[2] = LCA(a1, b2), p[3] = LCA(a2, b1),     p[4] = LCA(a2, b2);     sort(p + 1, p + 5, [](int a, int b) { return dep[a] > dep[b]; });     int A = p[1], B = p[2];     hh = 0, to = B, stk[top = 1] = A, dfs3(A), hh = 0, top = 1, dfs3(A), hh = 0,     top = 1, dfs3(A);   }   int main() {     int n, m;     scanf( %d%d , &n, &m);     for (int i = 1, a, b; i <= m; i++) {       scanf( %d%d , &a, &b);       if (a > b) swap(a, b);       G[a].push_back(b), G[b].push_back(a), e2[++ecnt2] = (edge){a, b, 0},                                             mp[pair<int, int>(a, b)] = ecnt2;     }     for (int i = 1; i <= n; i++)       if (!vis[i]) dfs(i, 0);     for (int i = 1; i <= ecnt2; i++)       if (!ok[i]) mark(e2[i].from, e2[i].to, i);     for (int i = 1; i <= n; i++)       if (!fa[i][0]) {         dfs2(i, 0);         if (flg) {           puts( YES ), work(e2[fir].from, e2[fir].to, e2[sec].from, e2[sec].to);           return 0;         }       }     puts( NO );     return 0;   }   