#include<bits/stdc++.h>
using namespace std;
#define M 1000005
#define ll long long
int n,q,fa[M],sz[M],dep[M];
vector<int>d[M];
void dfs(int x,int f){
	sz[x]=1;fa[x]=f;dep[x]=dep[f]+1;
	for(int i=0;i<(int)d[x].size();++i){
		int v=d[x][i];
		if(v==f)continue;
		dfs(v,x);sz[x]+=sz[v];
	}
}
int sk1[M],w1[M],sk2[M],w2[M];
int main(){
	scanf("%d%d",&n,&q);
	for(int i=1,x,y;i<n;++i){
		scanf("%d%d",&x,&y);
		d[x].push_back(y);
		d[y].push_back(x);
	}
	dfs(1,0);
	for(int i=1,x,y;i<=q;++i){
		scanf("%d%d",&x,&y);
		if(dep[x]<dep[y])swap(x,y);
		int cnt1=0,cnt2=0,pr1=0,pr2=0;
		while(dep[x]>dep[y]){
			sk1[++cnt1]=x;w1[cnt1]=sz[x]-pr1;
			pr1=sz[x];x=fa[x];
		}
		while(x!=y){
			sk1[++cnt1]=x;w1[cnt1]=sz[x]-pr1;pr1=sz[x];
			sk2[++cnt2]=y;w2[cnt2]=sz[y]-pr2;pr2=sz[y];
			x=fa[x];y=fa[y];
		}
		sk1[++cnt1]=x;w1[cnt1]=n-pr1-pr2;
		for(int j=cnt2;j>=1;--j)sk1[++cnt1]=sk2[j],w1[cnt1]=w2[j];
		ll ans=0;int sum=0,id=cnt1+1;
		for(int j=cnt1;j>=1;--j){
			if(cnt1-j+1>=j-1)break;
			sum+=w1[j];id=j;
		}
		for(int j=1;j<=cnt1&&id<=cnt1;++j){
			ans+=1ll*w1[j]*sum;
			sum-=w1[id];
			id++;
		}
		printf("%lld\n",ans);
	}
}