#include<bits/stdc++.h>
#define int long long
using namespace std;

int get() {
	int x = 0, f = 1; char c = getchar();
	while(!isdigit(c)) { if(c == '-') f = -1; c = getchar(); }
	while(isdigit(c)) { x = x * 10 + c - '0'; c = getchar(); }
	return x * f;
}

const int N = 1e6 + 5;
int n, q;
struct Edge { int v, nxt; } edge[N << 1];
int head[N], tot, sze[N], dep[N], fa[N];
int bin[N], top, sum[N];

void add(int u, int v) { edge[++tot] = (Edge){ v, head[u] }, head[u] = tot; }

void dfs(int u, int lst) {
	sze[u] = 1, dep[u] = dep[lst] + 1, fa[u] = lst;
	for(int i = head[u]; i; i = edge[i].nxt) {
		int v = edge[i].v;
		if(v == lst) continue;
		dfs(v, u), sze[u] += sze[v];
	}
}

int GetLCA(int x, int y) {
	if(dep[x] < dep[y]) 
		swap(x, y);
	while(dep[x] > dep[y]) 
		x = fa[x];
	if(x == y) return x;
	while(x != y) x = fa[x], y = fa[y];
	return x;
}

void extract(int x, int y) {
	int lca = GetLCA(x, y);
	top = 0;
	while(x != lca) bin[++top] = x, x = fa[x];
	top += dep[y] - dep[lca] + 1;
	int tail = top;
	while(y != lca) bin[tail--] = y, y = fa[y];
	bin[tail--] = lca;
	for(int i = 1; i <= top; i++) sum[i] = sze[bin[i]];
	for(int i = 1; i <= top; i++) {
		if(i > 1 && fa[bin[i - 1]] == bin[i]) sum[i] -= sze[bin[i - 1]];
		if(i < top && fa[bin[i + 1]] == bin[i]) sum[i] -= sze[bin[i + 1]];
		if(bin[i] == lca) sum[i] += n - sze[bin[i]];
	}
	for(int i = 1; i <= top; i++) sum[i] += sum[i - 1];
}

int GetSum(int l, int r) { return sum[r] - sum[l - 1]; }

main() {
	n = get(), q = get();
	for(int i = 1, u, v; i < n; i++) u = get(), v = get(), add(u, v), add(v, u);
	dfs(1, 0);
	for(int i = 1; i <= q; i++) {
		int x = get(), y = get();
		extract(x, y);
		int ans = 0;
		for(int j = 1; j + top / 2 + 1 <= top; j++)
			ans += GetSum(j + top / 2 + 1, top) * GetSum(j, j);
		printf("%lld\n", ans);
	}
	return 0;
}