func_code_string: #include <bits/stdc++.h>   using namespace std;   inline int gi() {     char c;     int num = 0, flg = 1;     while ((c = getchar()) <  0  || c >  9 )       if (c ==  - ) flg = -1;     while (c >=  0  && c <=  9 ) {       num = num * 10 + c - 48;       c = getchar();     }     return num * flg;   }   int n, m;   int fir[200005], cur[200005], to[5000005], nxt[5000005], cap[5000005],       id[2 * 200005], cnt;   void adde(int a, int b, int c, int d = 0) {     to[++cnt] = b;     nxt[cnt] = fir[a];     fir[a] = cnt;     cap[cnt] = c;     if (d) id[cnt] = d;     to[++cnt] = a;     nxt[cnt] = fir[b];     fir[b] = cnt;     cap[cnt] = 0;     if (d) id[cnt] = d;   }   int fa[200005], son[200005], sonp[200005], siz[200005], top[200005],       dep[200005];   void dfs1(int u) {     dep[u] = dep[fa[u]] + 1;     siz[u] = 1;     for (int v, p = fir[u]; p; p = nxt[p]) {       if ((v = to[p]) != fa[u]) {         fa[v] = u;         dfs1(v);         siz[u] += siz[v];         if (siz[son[u]] < siz[v]) son[u] = v, sonp[u] = p;       }     }   }   int pos[200005], dc, dfn[200005];   void dfs2(int u, int fro) {     pos[u] = ++dc;     dfn[dc] = id[fro];     if (son[u]) top[son[u]] = top[u], dfs2(son[u], sonp[u]);     for (int v, p = fir[u]; p; p = nxt[p])       if ((v = to[p]) != fa[u] && v != son[u]) top[v] = v, dfs2(v, p);   }   int S, T, sz;   const int INF = 0x3f3f3f3f;   struct node {     int l, r;   } a[200005];   int rt;   void build(int &i, int l, int r) {     if (l == r) {       i = dfn[l];       return;     }     i = ++sz;     int mid = (l + r) >> 1;     build(a[i].l, l, mid);     build(a[i].r, mid + 1, r);     adde(i, a[i].l, INF);     adde(i, a[i].r, INF);   }   void insert(int i, int l, int r, int ql, int qr, int p) {     if (l > qr || r < ql) return;     if (ql <= l && r <= qr) {       adde(p, i, INF);       return;     }     int mid = (l + r) >> 1;     insert(a[i].l, l, mid, ql, qr, p);     insert(a[i].r, mid + 1, r, ql, qr, p);   }   void QP(int x, int y, int p) {     while (top[x] != top[y]) {       if (dep[top[x]] < dep[top[y]]) swap(x, y);       insert(rt, 1, n, pos[top[x]], pos[x], p);       x = fa[top[x]];     }     if (dep[x] > dep[y]) swap(x, y);     insert(rt, 1, n, pos[x] + 1, pos[y], p);   }   queue<int> q;   int dis[200005];   bool bfs() {     for (int i = 1; i <= sz; i++) dis[i] = -1;     q.push(T);     dis[T] = 0;     while (!q.empty()) {       int u = q.front();       q.pop();       for (int v, p = fir[u]; p; p = nxt[p]) {         v = to[p];         if (cap[p ^ 1] > 0 && dis[v] == -1) {           dis[v] = dis[u] + 1;           q.push(v);         }       }     }     return dis[S] != -1;   }   int sap(int u, int aug) {     if (u == T) return aug;     int tmp, ret = 0;     for (int v, &p = cur[u]; p; p = nxt[p]) {       v = to[p];       if (cap[p] > 0 && dis[u] == dis[v] + 1) {         tmp = sap(v, min(cap[p], aug));         cap[p] -= tmp;         aug -= tmp;         cap[p ^ 1] += tmp;         ret += tmp;         if (!aug) break;       }     }     return ret;   }   int flow;   void maxflow() {     flow = 0;     while (bfs()) {       for (int i = 1; i <= sz; i++) cur[i] = fir[i];       flow += sap(S, INF);     }   }   int main() {     int i, u, v;     n = gi();     m = gi();     for (i = 1; i < n; i++) {       u = gi();       v = gi();       adde(u, v, 0, i);     }     dfs1(1);     top[1] = 1;     dfs2(1, 0);     memset(fir, 0, sizeof(fir));     cnt = 1;     sz = n;     build(rt, 1, n);     for (i = 1; i <= m; i++) {       u = gi();       v = gi();       QP(u, v, sz + i);     }     S = sz + m + 1;     T = sz + m + 2;     int tot = sz;     for (i = 1; i < n; i++) adde(i, T, 1);     for (i = 1; i <= m; i++) adde(S, sz + i, 1);     sz = T;     maxflow();     printf( %d n , flow);     int cnt1 = 0, cnt2 = 0;     for (i = 1; i <= m; i++)       if (dis[tot + i] != -1) cnt1++;     for (i = 1; i < n; i++)       if (dis[i] == -1) cnt2++;     printf( %d , cnt1);     for (i = 1; i <= m; i++)       if (dis[tot + i] != -1) printf(  %d , i);     printf(  n );     printf( %d , cnt2);     for (i = 1; i < n; i++)       if (dis[i] == -1) printf(  %d , i);     printf(  n );   }   