#define ATCODER #define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using ll = long long; using ld = long double; using pll = pair; using pdd = pair; //template using pq = priority_queue, greater>; #define FOR(i, a, b) for(ll i=(a); i<(b);i++) #define REP(i, n) for(ll i=0; i<(n);i++) #define ROF(i, a, b) for(ll i=(b-1); i>=(a);i--) #define PER(i, n) for(ll i=n-1; i>=0;i--) #define REPREP(i,j,a,b) for(ll i=0;i > #define VV2(type,n,m,val) vector< vector > val;val.resize(n);for(ll i;i #define VEC(type,n,val) vector val;val.resize(n) #define VL vector #define VVL vector< vector > #define VP vector< pair > #define SZ size() #define all(i) begin(i),end(i) #define SORT(i) sort(all(i)) #define BITI(i) (1<>i) & 1) != 0) #define ALLBIT(n) (ll(1)<v?v:n #define MP(a,b) make_pair(a,b) #define DET2(x1,y1,x2,y2) x1*y2-x2*y1 #define DET3(x1,y1,z1,x2,y2,z2,x3,y3,z3) x1*y2*z3+x2*y3*z1+x3*y1*z2-z1*y2*x3-z2*y3*x1-z3*y1*x2 #define INC(a) for(auto& v:a)v++; #define DEC(a) for(auto& v:a)v--; #define SQU(x) (x)*(x) #define L0 ll(0) #ifdef ATCODER #include using namespace atcoder; using mint = modint1000000007; using mint2 = modint998244353; #endif template vector read(size_t n) { vector ts(n); for (size_t i = 0; i < n; i++) cin >> ts[i]; return ts; } template void read_tuple_impl(TV&) {} template void read_tuple_impl(TV& ts) { get(ts).emplace_back(*(istream_iterator(cin))); read_tuple_impl(ts); } template decltype(auto) read_tuple(size_t n) { tuple...> ts; for (size_t i = 0; i < n; i++) read_tuple_impl(ts); return ts; } using val = ll; using func = ll; val op(val a, val b) { return a + b; } val e() { return 0; } val mp(func f, val a) { if (f == -1) return a; return f; } func comp(func f, func g) { if (f == -1) return g; return f; } func id() { return -1; } ll di[4] = { 1,0,-1,0 }; ll dj[4] = { 0,1,0,-1 }; //ll di[4] = { -1,-1,1,1 }; //ll dj[4] = { -1,1,-1,1 }; ll di8[8] = { 0,-1,-1,-1,0,1,1,1 }; ll dj8[8] = { -1,-1,0,1,1,1,0,-1 }; ll n; VVL g; VVL c; VL d; vector lc; VL pc; ll dfs(ll now, ll p) { ll res = 1; pc[now] = n - 1; REP(i, g[now].size()) { ll v = g[now][i]; if (v == p) continue; lc[v][0]=MP(now,i); d[v] = d[now] + 1; ll r = dfs(v, now); pc[now] -= r; c[now][i] = r; res += r; } return res; } void solve() { ll q; cin >> n >> q; g.resize(n); c.resize(n); d.resize(n); lc.resize(n); pc.resize(n); REP(i, n - 1) { ll a, b; cin >> a >> b; a--; b--; g[a].push_back(b); g[b].push_back(a); } REP(i, n) { c[i].resize(g[i].size(), -1); lc[i].resize(20, MP(-1, -1)); } dfs(0, -1); REP(i, 19) { REP(j, n) { auto [v, in] = lc[j][i]; if (v >= 0) lc[j][i + 1] = lc[v][i]; } } while (q--) { ll s, t; cin >> s >> t; s--; t--; if (d[s] < d[t]) swap(s, t); ll ss = s; ll tt = t; if ((d[ss] + d[tt]) % 2) { cout << 0 << "\n"; continue; } PER(i, 20) { ll up = ll(1) << i; if (d[ss] - up < d[tt]) continue; ss = lc[ss][i].first; } ll lca; if (ss != tt) { PER(i, 20) { if (lc[ss][i].first != lc[tt][i].first) { ss = lc[ss][i].first; tt = lc[tt][i].first; } } lca = lc[ss][0].first; } else { lca = ss; } if (d[s] == d[t]) { cout << n - c[lca][lc[ss][0].second] - c[lca][lc[tt][0].second] << "\n"; } else{ ll dd = lca + (d[s] - d[t]) / 2; ll sss = s; PER(i, 20) { ll up = ll(1) << i; if (d[sss] - up <= dd) continue; sss = lc[sss][i].first; } auto [p, ip] = lc[sss][0]; cout << n - pc[p] - c[p][ip] << "\n"; } } } int main() { ll t = 1; //cin >> t; while (t--) { solve(); } return 0; }