#include<cstdio>

#include<algorithm>

#define N (1010)

#define rg register

#define LL long long

using namespace std;

int n,m,root,cnt,tot,dep[N],in[N],out[N],fa[N],last[N],a[N][N];

LL ans=0;

struct edge{

	int to,pre,dis;

}e[N<<1];

inline int read(){

	int k=0,f=1; char c=getchar();

	while(c<'0'||c>'9')c=='-'&&(f=-1),c=getchar();

	while('0'<=c&&c<='9')k=k*10+c-'0',c=getchar();

	return k*f;

}

inline void add(int x,int y,int z){e[++tot]=(edge){y,last[x],z}; last[x]=tot;}

void dfs(int x,int father){

	in[x]=++cnt; dep[x]=dep[father]+1;

	for(rg int i=last[x],to;i;i=e[i].pre) if((to=e[i].to)!=father) dfs(to,fa[to]=x);

	out[x]=++cnt;

}

inline bool IN(int x,int y){

	if(in[y]<=in[x]&&out[x]<=out[y]) return 1;

	return 0;

}

int main(){

	n=read(); m=read();

	for(rg int i=1,u,v,dis;i<n;i++){

		u=read(),v=read(),dis=read();

		add(u,v,dis),add(v,u,dis);

		a[u][v]=a[v][u]=dis;

	}

	dfs(1,0);

	//for(int i=1;i<=n;i++) printf("%d %d\n",in[i],out[i]);

	for(rg int i=1,x,y;i<=m;i++){

		x=read(); y=read(); ans=0;

		if(dep[x]<dep[y]) swap(x,y);

		while(!IN(y,x)) ans+=a[x][fa[x]],x=fa[x];

		while(x!=y) ans+=a[y][fa[y]],y=fa[y];

		printf("%lld\n",ans);

	}

	return 0;

}