#include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef templete #define rep(i,a,b) for(int i=a;i=b;i--) #define fore(i,a) for(auto &i:a) #define all(x) (x).begin(),(x).end() //#include //using namespace boost::multiprecision; using namespace std; using namespace atcoder; //using atmint = modint998244353; using atmint = modint; using Graph = vector>; using P = pair; //#pragma GCC optimize ("-O3") using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); } typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60; templatebool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; } templatebool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; } //--------------------------------------------------------------------------------------------------- template struct ModInt { static const int Mod = MOD; unsigned x; ModInt() : x(0) { } ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; } ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; } int get() const { return (int)x; } ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; } ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; } ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; } ModInt &operator/=(ModInt that) { return *this *= that.inverse(); } ModInt operator+(ModInt that) const { return ModInt(*this) += that; } ModInt operator-(ModInt that) const { return ModInt(*this) -= that; } ModInt operator*(ModInt that) const { return ModInt(*this) *= that; } ModInt operator/(ModInt that) const { return ModInt(*this) /= that; } ModInt inverse() const { long long a = x, b = MOD, u = 1, v = 0; while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); } return ModInt(u); } bool operator==(ModInt that) const { return x == that.x; } bool operator!=(ModInt that) const { return x != that.x; } ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; } }; template ostream& operator<<(ostream& st, const ModInt a) { st << a.get(); return st; }; template ModInt operator^(ModInt a, unsigned long long k) { ModInt r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; } template struct Comb { vector fac, ifac; Comb(){fac.resize(FAC_MAX,1);ifac.resize(FAC_MAX,1);rep(i,1,FAC_MAX)fac[i]=fac[i-1]*i; ifac[FAC_MAX-1]=T(1)/fac[FAC_MAX-1];rrep(i,FAC_MAX-2,1)ifac[i]=ifac[i+1]*T(i+1);} T aPb(int a, int b) { if (b < 0 || a < b) return T(0); return fac[a] * ifac[a - b]; } T aCb(int a, int b) { if (b < 0 || a < b) return T(0); return fac[a] * ifac[a - b] * ifac[b]; } T nHk(int n, int k) { if (n == 0 && k == 0) return T(1); if (n <= 0 || k < 0) return 0; return aCb(n + k - 1, k); } // nHk = (n+k-1)Ck : n is separator T pairCombination(int n) {if(n%2==1)return T(0);return fac[n]*ifac[n/2]/(T(2)^(n/2));} // combination of paris for n com.aCb(h+w-2,h-1); }; //typedef ModInt<1000000007> mint; typedef ModInt<998244353> mint; //typedef ModInt<1000000000> mint; Comb com; //vector dp(n+1,vector(n+1,vector(n+1,0))); //vector dp(n+1,vector(n+1,0)); std::random_device seed_gen; std::mt19937 engine(seed_gen()); string ye = "Yes"; string no = "No"; string draw = "Draw"; #endif // templete //--------------------------------------------------------------------------------------------------- struct LCA { vector> parent; // parent[k][u]:= u の 2^k 先の親 vector> max_w; // max_w[k][u]:= u の 2^k 先までの辺をたどった時の最大の重み vector dist; // root からの距離 vector child_cnt; // child LCA(const Graph &G, map & cost,int root = 0) { init(G, cost, root); } // 初期化 void init(const Graph &G, map & cost, int root = 0) { int V = G.size(); int K = 1; while ((1 << K) < V) K++; parent.assign(K, vector(V, -1)); max_w.assign(K, vector(V, -infl)); dist.assign(V, -1); child_cnt.assign(V, 0); dfs(G, cost, root, -1, 0); for (int k = 0; k + 1 < K; k++) { for (int v = 0; v < V; v++) { if (parent[k][v] < 0) { parent[k + 1][v] = -1; } else { parent[k + 1][v] = parent[k][parent[k][v]]; max_w[k + 1][v] = max(max_w[k][v],max_w[k][parent[k][v]]); } } } } // 根からの距離と1つ先の頂点を求める int dfs(const Graph &G, map & cost, int v, int p, int d) { int cnt = 0; parent[0][v] = p; if(p == -1) max_w[0][v] = -infl; else max_w[0][v] = cost[{v,p}]; dist[v] = d; for (auto e : G[v]) { if (e != p) cnt += dfs(G, cost, e, v, d + 1); } child_cnt[v] = cnt + 1; return child_cnt[v]; } int query(int u, int v) { if (dist[u] < dist[v]) swap(u, v); // u の方が深いとする int K = parent.size(); // LCA までの距離を同じにする for (int k = 0; k < K; k++) { if ((dist[u] - dist[v]) >> k & 1) { u = parent[k][u]; } } // 二分探索で LCA を求める if (u == v) return u; for (int k = K - 1; k >= 0; k--) { if (parent[k][u] != parent[k][v]) { u = parent[k][u]; v = parent[k][v]; } } return parent[0][u]; } int query2(int u, int dep) { int K = parent.size(); for (int k = 0; k < K; k++) { if (dep >> k & 1) { u = parent[k][u]; } } return u; } // u,vとlca(u,v)間を結ぶ辺のうち、最大の重みの辺を求める ll query_max_w(int u, int v) { ll res = 0; if (dist[u] < dist[v]) swap(u, v); // u の方が深いとする int K = parent.size(); // LCA までの距離を同じにする for (int k = 0; k < K; k++) { if ((dist[u] - dist[v]) >> k & 1) { chmax(res,max_w[k][u]); u = parent[k][u]; } } // 二分探索で LCA を求める if (u == v) return res; for (int k = K - 1; k >= 0; k--) { if (parent[k][u] != parent[k][v]) { chmax(res,max_w[k][u]); chmax(res,max_w[k][v]); u = parent[k][u]; v = parent[k][v]; } } chmax(res,max_w[0][u]); chmax(res,max_w[0][v]); return res; } int get_dist(int u, int v) { return dist[u] + dist[v] - 2 * dist[query(u, v)]; } int query3(int s, int t){ //cout << dist[s] << " " << dist[t] << endl; if(dist[s] != dist[t]){ // cout << "!=" << endl; ll d = get_dist(s,t); if(d % 2 == 0)return 1 + child_cnt[0]; else return 0 + child_cnt[0]; }else{ ll l = query(s,t); ll sval = dist[s] - dist[l] - 1; ll tval = dist[t] - dist[l] - 1; ll dep_s_p = query2(s,sval); ll dep_t_p = query2(t,tval); // cout << dep_s_p << " " << dep_t_p << endl; // cout << child_cnt[dep_s_p] << " " << child_cnt[dep_t_p] << endl; // cout << child_cnt[0] << " " << endl; //return int(G.size()) - child_cnt[dep_s_p] - child_cnt[dep_t_p]; return child_cnt[dep_s_p] + child_cnt[dep_t_p]; } } bool is_on_path(int u, int v, int a) { return get_dist(u, a) + get_dist(a, v) == get_dist(u, v); } }; void _main() { ll n,q; cin >> n >> q; Graph g(n); rep(i,0,n-1){ ll a,b; cin >> a >> b; a--; b--; g[a].push_back(b); g[b].push_back(a); } mapmp; LCA lca(g,mp,0); rep(qi,0,q){ ll s,t; cin >> s >> t; s--; t--; cout << n - lca.query3(s,t) << endl; } }