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

typedef long long ll;
typedef pair <int,int> Pii;
typedef double db;
#define pb push_back
#define mp make_pair
#define rep(i,a,b) for(int i=a,i##end=b;i<=i##end;++i)
#define drep(i,a,b) for(int i=a,i##end=b;i>=i##end;--i)
template <class T> inline void cmin(T &a, T b){ ((a>b)&&(a=b)); }
template <class T> inline void cmax(T &a, T b){ ((a<b)&&(a=b)); }

template <class T = int> T rd() {
	T s = 0; int f = 0; char c;
	while(c = getchar(), c < 48) f = c == '-';
	do s = s * 10 + c  -48;
	while(c = getchar(), c > 47);
	return f? -s:s;
}

const int N = 1e6 + 10;
const ll LINF = 1e18 + 10;


int n, m;
vector <int> G[N];
int siz[N], dep[N], fa[N];

void dfs(int u ,int f = 0) {
	siz[u] = 1,dep[u]=dep[fa[u]=f]+1;
	for(int v:G[u]) if(v!=f) {
		dfs(v,u);
		siz[u] += siz[v];
	}
}

int A[N], AC;
int B[N], BC;


int main() {
	n=rd(),m=rd();
	rep(i,2,n) {
		int u =rd(),v=rd();
		G[u].pb(v),G[v].pb(u);
	}
	dfs(1);
	while(m--) {
		int x = rd(),y=rd(),a=0,b=0;
		AC=BC=0;
		while(x != y) {
			if(dep[x] > dep[y]) {
				A[++AC] = siz[x] - a;
				a = siz[x];
				x= fa[x];
			} else{
				B[++BC] = siz[y] - b;
				b = siz[y];
				y= fa[y];
			}
		}
		vector <int> v;
		rep(i,1,AC) v.pb(A[i]);
		v.pb(n - a - b);
		drep(i,BC,1) v.pb(B[i]);
		int j = v.size()-1, s = 0;
		ll ans = 0;
		drep(i,v.size()-1,0) {
			while(~j && i + (int)v.size() - j < j - i) s += v[j--];
			ans += 1ll * v[i] * s;
		}
		printf("%lld\n", ans);
	}
}