#include <bits/stdc++.h>
typedef long long ll;
const int N=1000005,W=20;
int f[N],n,Q,x,y,to[N<<1],edge,last[N],Next[N<<1],siz[N],dep[N],a[N],b[N],suf[N];
void add(int x,int y){
	to[++edge]=y;
	Next[edge]=last[x];
	last[x]=edge;
}
void dfs(int x,int fa){
	f[x]=fa,dep[x]=dep[fa]+1;
	siz[x]=1;
	for (int i=last[x];i;i=Next[i]){
		int u=to[i];
		if (u==fa) continue;
		dfs(u,x);
		siz[x]+=siz[u];
	}
}
void solve(int x,int y){
	int lstx=0,lsty=0,cntx=0,cnty=0,dis=0;
	while (x!=y){
		if (dep[x]>dep[y]){
			a[++cntx]=siz[x]-lstx;
			lstx=siz[x];
			x=f[x];
		}else{
			b[++cnty]=siz[y]-lsty;
			lsty=siz[y];
			y=f[y];
		}
		dis++;
	}
	a[++cntx]=n-lstx-lsty;
	for (int i=cnty;i>=1;i--)
		a[++cntx]=b[i];
	suf[cntx]=a[cntx];
	for (int i=cntx-1;i>=1;i--)
		suf[i]=a[i]+suf[i+1];
	ll ans=0;
	for (int i=1,r=2+(dis+1)/2;i<=cntx/2 && r<=cntx;i++,r++)
		ans+=(ll)a[i]*suf[r];
	printf("%lld\n",ans);	
}
int main(){
	scanf("%d%d",&n,&Q);
	for (int i=1;i<n;i++){
		scanf("%d%d",&x,&y);
		add(x,y),add(y,x);
	}
	dfs(1,0);
	while (Q--){
		scanf("%d%d",&x,&y);
		solve(x,y);
	}
}