#include<cstdio>
    #include<vector>
    #include<iostream>
    using namespace std;
    vector<pair<int,int> >e[1005];
    int fa[1005],n,q,ans,deep[1005]={0,1},map[1005][1005],u,v,w;
    void dfs(int now){
        for(int i=0;i<e[now].size();i++){
            if(e[now][i].first!=fa[now]){
                fa[e[now][i].first]=now;
                deep[e[now][i].first]=deep[now]+1;
                dfs(e[now][i].first);
            }
        }
    }
    int main(){
        freopen("pwalk.in","r",stdin);
        freopen("pwalk.out","w",stdout);
        scanf("%d%d",&n,&q);
        for(int i=1;i<n;i++){
            scanf("%d%d%d",&u,&v,&w);
            e[u].push_back(make_pair(v,w));
            e[v].push_back(make_pair(u,w));
            map[u][v]=map[v][u]=w;
        }
        dfs(1);
        for(int i=1;i<=q;i++){
            scanf("%d%d",&u,&v);
            ans=0;
            while(u!=v){
                if(deep[u]<deep[v]) swap(u,v);
                ans+=map[fa[u]][u];
                u=fa[u];
            }
            printf("%d\n",ans);
        }
    }