func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 1e5 + 10;   const int maxlog = 24;   int par[maxn][maxlog], h[maxn];   int siz[maxn];   bool mark[maxn];   int n;   vector<int> adj[maxn];   void dfs(int x) {     mark[x] = 1;     for (int i = 0; i < adj[x].size(); i++) {       int child = adj[x][i];       if (!mark[child]) {         par[child][0] = x;         h[child] = h[x] + 1;         dfs(child);         siz[x] += siz[child] + 1;       }     }   }   int LCAH(int fi, int se) {     for (int i = maxlog - 1; i >= 0; i--)       if (par[fi][i] != par[se][i]) {         fi = par[fi][i];         se = par[se][i];       }     return n - siz[fi] - siz[se] - 2;   }   int LCA(int fi, int se) {     for (int i = maxlog - 1; i >= 0; i--)       if (h[par[fi][i]] >= h[se]) fi = par[fi][i];     if (fi == se) return fi;     for (int i = maxlog - 1; i >= 0; i--)       if (par[fi][i] != par[se][i]) {         fi = par[fi][i];         se = par[se][i];       }     return par[fi][0];   }   int main() {     cin >> n;     for (int i = 1; i < n; i++) {       int fi, se;       cin >> fi >> se;       adj[fi].push_back(se);       adj[se].push_back(fi);     }     dfs(1);     for (int j = 1; j < maxlog; j++)       for (int i = 1; i <= n; i++) par[i][j] = par[par[i][j - 1]][j - 1];     int q;     cin >> q;     while (q--) {       int fi, se;       cin >> fi >> se;       if (h[fi] < h[se]) swap(fi, se);       int dis = h[fi] + h[se] - 2 * h[LCA(fi, se)];       if (fi == se)         cout << n << endl;       else if (dis % 2 == 1)         cout << 0 << endl;       else if (h[fi] == h[se]) {         cout << LCAH(fi, se) << endl;       } else {         dis /= 2;         se = fi;         for (int i = maxlog - 1; i >= 0; i--) {           if ((1 << i) & dis) {             fi = par[fi][i];           }         }         int k = dis - 1;         for (int i = maxlog - 1; i >= 0; i--) {           if ((1 << i) & k) {             se = par[se][i];           }         }         cout << siz[fi] - siz[se] << endl;       }     }     return 0;   }   