#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
using namespace std;
int n,q,mp[1010][1010]={0},a[1010][1010]={0},num[1010];
int h,t,jd[1010];
void bfs(int st)
{
	bool pd[1010]={0};
	h=0;
	t=1;
	jd[1]=st;
	pd[st]=1;
	while(h!=t)
	{
		++h;
		for(int i=1;i<=num[jd[h]];++i)
		{
			if(pd[mp[jd[h]][i]]==0)
			{
				++t;
				jd[t]=mp[jd[h]][i];
				pd[jd[t]]=1;
				a[st][jd[t]]=a[st][jd[h]]+a[jd[h]][jd[t]];
			}
		}
	}
}
int main()
{
	freopen("pwalk.in","r",stdin);
	freopen("pwalk.out","w",stdout);
	scanf("%d%d",&n,&q);
	for(int i=1;i<n;++i)
	{
		int t1,t2,t3;
		scanf("%d%d%d",&t1,&t2,&t3);
		a[t1][t2]=a[t2][t1]=t3;
		mp[t1][++num[t1]]=t2;
		mp[t2][++num[t2]]=t1;
	}
	/*
	for(int i=1;i<=n;++i)
	{
		for(int j=1;j<=n;++j)
		{
			cout<<a[i][j]<<' ';
		}
		cout<<endl;
	}
	cout<<endl;
	*/
	for(int i=1;i<=n;++i)
	{
		bfs(i);
	}
	/*
	for(int i=1;i<=n;++i)
	{
		for(int j=1;j<=n;++j)
		{
			cout<<a[i][j]<<' ';
		}
		cout<<endl;
	}
	cout<<endl;
	*/
	for(int i=1;i<=q;++i)
	{
		int t1,t2;
		scanf("%d%d",&t1,&t2);
		printf("%d\n",a[t1][t2]);
	}
	return 0;
}