#include <bits/stdc++.h>

#define rep(i, x, y) for(int i = (x); i <= (y); i++)
#define per(i, x, y) for(int i = (x); i >= (y); i--)
#define eb emplace_back

using namespace std;

using vec = vector < int >;
using ll = long long;

template < typename T > void chkmin(T &x, const T &y) { x = x < y ? x : y; }

const int N = 1e6 + 10;
const int M = 1e7 + 10;

int n, q;

#define in read()

int read() { int x; scanf("%d", &x); return x; }

vec G[N];
int siz[N], dep[N], fa[N];

void dfs(int x, int p) {
	fa[x] = p; dep[x] = dep[p] + 1; siz[x] = 1;
	for(auto y : G[x]) if(y ^ p) dfs(y, x), siz[x] += siz[y];
}

int id[M], tot, tsz[M];
int ssz[M];

int lca(int x, int y) {
	if(dep[x] < dep[y]) swap(x, y);
	tot = 0;
	vec pot, tpot;
	while(dep[x] > dep[y]) {
		pot.eb(x), x = fa[x];
	}
	while(x != y) pot.eb(x), tpot.eb(y), x = fa[x], y = fa[y];
	pot.eb(x); reverse(pot.begin(), pot.end()), reverse(tpot.begin(), tpot.end());
	tot = pot.size() + tpot.size();
	rep(i, 1, tot) {
		if(pot.size()) id[i] = pot.back(), pot.pop_back();
		else if(tpot.size()) id[i] = tpot.back(), tpot.pop_back();
	}
	rep(i, 1, tot) tsz[i] = siz[id[i]];
	tsz[0] = tsz[tot + 1] = 0;
	bool isl = 1;
	rep(i, 1, tot) {
		if(isl && i > 1) tsz[i] -= siz[id[i - 1]];
		if(!isl && i < tot) tsz[i] -= siz[id[i + 1]];
		if(id[i] == x) tsz[i] -= siz[id[i + 1]], isl = 0, tsz[i] += n - siz[x];
	}
	rep(i, 1, tot) ssz[i] = ssz[i - 1] + tsz[i];
	return x;
}

int main() {
#ifdef YJR_2333_TEST
	freopen("1.in", "r", stdin);
#endif
	n = in, q = in; rep(i, 1, n - 1) { int u = in, v = in; G[u].eb(v), G[v].eb(u); }
	dfs(1, 0);
	rep(i, 1, q) {
		int x = in, y = in;
		int L = lca(x, y); // unused
		ll ans = 0;
		//cerr << L << endl;
		//rep(x, 1, tot) cerr << id[x] << " "; cerr << endl;
		//rep(x, 1, tot) cerr << tsz[x] << " "; cerr << endl;
		rep(x, 1, tot) {
			int l = 1, r = (2 * x - tot - 1) / 2;
			//cerr << x << " " << l << " " << r << endl;
			if(l <= r) ans += (ssz[r] - ssz[l - 1]) * 1ll * tsz[x];
			l = (2 * x + tot + 2) >> 1, r =  tot;
			//cerr << x << " " << l << " " << r << endl;
			if(l <= r) ans += (ssz[r] - ssz[l - 1]) * 1ll * tsz[x];
		} ans /= 2; printf("%lld\n", ans);
	}
}