#include<cstdio>

 #include<cstring>

 #include<iostream>

 using namespace std;

 const int maxn=,max_log=;

 int N,Q,F[maxn+][max_log+],edge_head[maxn+],num_edge=,c,Dep[maxn+],u,v,w,A,B;

 int Sig[maxn+];

 struct Edge{

     int to,nx,dis;

 }edge[(maxn<<)+];

 inline void Add_edge(int from,int to,int dis){

     edge[++num_edge].nx=edge_head[from];

     edge[num_edge].to=to;

     edge[num_edge].dis=dis;

     edge_head[from]=num_edge;

     return;

 }

 inline void Dfs(int x,int fa){

     Dep[x]=Dep[fa]+;

     F[x][]=fa;

     for(int i=;i<=max_log;i++)

         F[x][i]=F[F[x][i-]][i-];

     for(int i=edge_head[x];i;i=edge[i].nx){

         int y=edge[i].to;

         if(y==fa)continue;

         Sig[y]=Sig[x]+edge[i].dis;

         Dfs(y,x);

     }

     return;

 }

 inline int LCA(int x,int y){

     if(Dep[x]<Dep[y]){

         int t=x;x=y;y=t;

     }

     for(int i=max_log;i>=;i--){

         int a;a=F[x][i];

         if(Dep[a]>=Dep[y])x=a;

         if(x==y)return x;

     }

     for(int i=max_log;i>=;i--){

         int a,b;a=F[x][i];b=F[y][i];

         if(a!=b){

             x=a;y=b;

         }

     }

     return F[x][];

 }

 int main(){

     scanf("%d%d",&N,&Q);

     for(int i=;i<N;i++){

         scanf("%d%d%d",&u,&v,&w);

         Add_edge(u,v,w);

         Add_edge(v,u,w);

     }

     Dfs(,);

     while(Q--){

         scanf("%d%d",&A,&B);

         c=LCA(A,B);

         printf("%d\n",Sig[A]+Sig[B]-Sig[c]-Sig[c]);

     }

     return ;

 }