#include<iostream> #include<cstdio> using namespace std; int n,q,cnt,fa[1001][11],deep[1001],head[1001],dis[1001]; bool vis[1001]; struct data{ int to,next,v; }e[1001]; void ins(int u,int v,int w){ e[++cnt].to=v; e[cnt].v=w; e[cnt].next=head[u]; head[u]=cnt; } void insert(int u,int v,int w){ ins(u,v,w);ins(v,u,w); } void dfs(int x){ vis[x]=true; for(int i=1;i<=9;i++){ if(deep[x]<(1<<i))break; fa[x][i]=fa[fa[x][i-1]][i-1]; } for(int i=head[x];i;i=e[i].next){ if(vis[e[i].to])continue; deep[e[i].to]=deep[x]+1; dis[e[i].to]=dis[x]+e[i].v; fa[e[i].to][0]=x; dfs(e[i].to); } } int lca(int x,int y){ if(deep[x]<deep[y])swap(x,y); int d=deep[x]-deep[y]; for(int i=0;i<=9;i++) if((1<<i)&d)x=fa[x][i]; for(int i=9;i>=0;i--) if(fa[x][i]!=fa[y][i]) x=fa[x][i],y=fa[y][i]; if(x==y)return x; else return fa[x][0]; } int main(){ scanf("%d%d",&n,&q); for(int i=1;i<n;i++){ int a,b,l; scanf("%d%d%d",&a,&b,&l); insert(a,b,l); }dfs(1); for(int i=1;i<=q;i++){ int a,b; scanf("%d%d",&a,&b); printf("%d\n",dis[a]+dis[b]-2*dis[lca(a,b)]); } return 0; }