#include <algorithm>
#include <cstdio>
#include <vector>
#include <cstring>
#include <queue>
using namespace std;
vector<int>A[10001];
vector<int>C[10001];
int dis[10001];
int vis[10001];
struct qd{
	int s,t;
}E[20001];
int n;
queue<int>q;
bool cmp(qd a,qd b){
	return a.s<b.s;
}
void spfa(int x){
	memset(dis,127/2,sizeof(dis));
	memset(vis,0,sizeof(vis));
	dis[x]=0;
	vis[x]=1;
	q.push(x);
	while(!q.empty()){
		int cd=q.front();
		q.pop();
		vis[cd]=0;
		for(int i=0;i<A[cd].size();i++){
			int u=A[cd][i];
			if(dis[u]>dis[cd]+C[cd][i]){
				dis[u]=dis[cd]+C[cd][i];
				if(!vis[u]){
					vis[u]=1;
					q.push(u);
				}	
			}
		}
	}
}
int main(){
	freopen("distance.in","r",stdin);
	freopen("distance.out","w",stdout);
	int m;
	scanf("%d %d",&n,&m);
	int x,y,z;
	for(int i=1;i<n;i++){
		scanf("%d %d %d",&x,&y,&z);
		A[x].push_back(y);
		A[y].push_back(x);
		C[x].push_back(z);
		C[y].push_back(z);
	}
	for(int i=1;i<=m;i++){
		scanf("%d %d",&x,&y);
		E[i].s=min(x,y);
		E[i].t=max(x,y);
	}
	sort(E+1,E+m+1,cmp);
	int last=0;
	for(int i=1;i<=m;i++){
		if(last!=E[i].s){
			spfa(E[i].s);
			last=E[i].s;
		}
		printf("%d\n",dis[E[i].t]);
	}
return 0;
}