#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define MP make_pair
mt19937 rnd(time(0));
const int MAXN=1e5+5;
int n,q;
struct edge{
	int v,w;
	edge(int _v=0,int _w=0){v=_v,w=_w;} 
};
struct query{
	int v,id;
	query(int _v=0,int _i=0){v=_v,id=_i;} 
};
struct node{
	ll w,c,fr;
	node(ll _w=-1e18,ll _c=-1,ll _f=0){w=_w,c=_c,fr=_f;} 
};
vector<edge> edg1[MAXN],edg2[MAXN];
vector<int> vir[MAXN];
vector<query> que[MAXN];
ll dep2[MAXN],dep1[MAXN],in[MAXN],tot;
ll ex[MAXN];// 该点属性 
node b1[MAXN],b2[MAXN];// 维护最优点 
int siz[MAXN],maxx[MAXN],col[MAXN],son,tsiz;
ll ans[MAXN<<3];
bool vis[MAXN];
struct LCA_tech{
int a[20][MAXN<<1],lg[MAXN<<1];
int chk(int x,int y){
	return dep2[x]<dep2[y]?x:y;
}
void build(){
	for(int i=2;i<(MAXN<<1);i++) lg[i]=lg[i>>1]+1; 
	for(int i=1;i<20;i++)
		for(int j=1;j+(1<<i)-1<=tot;j++)
			a[i][j]=chk(a[i-1][j],a[i-1][j+(1<<i-1)]);
}
int lca(int x,int y){
	x=in[x],y=in[y];
	if(x>y) swap(x,y);
	int k=lg[y-x+1];
	return chk(a[k][x],a[k][y-(1<<k)+1]);
}
}T2;
void dfs(int u,int fa){
	T2.a[0][++tot]=u;in[u]=tot;
	for(auto e:edg2[u]) if(e.v!=fa){
		dep2[e.v]=dep2[u]+e.w;
		dfs(e.v,u);
		T2.a[0][++tot]=u;
	}
}// init for T2
void get_size(int u,int fa){
	maxx[u]=siz[u]=1;
	for(auto e:edg1[u]) if(e.v!=fa&&!vis[e.v]){
		get_size(e.v,u);
		maxx[u]=max(maxx[u],siz[e.v]);
		siz[u]+=siz[e.v];
	}
	maxx[u]=max(maxx[u],tsiz-siz[u]);
	if(maxx[u]<maxx[son]) son=u;
}
void build_vir(vector<int> a){
	static int st[MAXN],top;
	st[top=1]=1;
	sort(a.begin(),a.end(),[&](int x,int y){return in[x]<in[y];});
	a.erase(unique(a.begin(),a.end()),a.end());
	auto link=[&](int u,int v){
		vir[u].push_back(v);
		vir[v].push_back(u);
	};
	for(int u:a) if(u!=1){
		int p=T2.lca(u,st[top]);
		while(st[top]!=p){
			if(dep2[st[top-1]]>=dep2[p]) link(st[top],st[top-1]),top--;
			else{
				link(st[top],p);
				st[top]=p;
			}
		}
		st[++top]=u;
	}
	while(top>1) link(st[top-1],st[top]),top--; 
}
void dfz(int r){
	vis[r]=true;
	vector<int> nd;
	auto dfs=[&](auto self,int u,int fa)->void{
		nd.push_back(u);ex[u]=dep1[u];
		for(query q:que[u]) nd.push_back(q.v);
		for(edge e:edg1[u]) if(e.v!=fa&&!vis[e.v]){
			dep1[e.v]=dep1[u]+e.w;
			col[e.v]=(u==r?e.v:col[u]);
			self(self,e.v,u);
		}
	};dep1[r]=0;dfs(dfs,r,0);col[r]=r;
//	cout<<"BUILD VIR: ";
//	for(int j:nd) cout<<j<<' ';cout<<endl;
	build_vir(nd);
//	cout<<"VIRTURE TREE "<<r<<endl;
//	for(int i=1;i<=n;i++){
//		for(int j:vir[i]) if(i<j) cout<<"EDGE "<<i<<' '<<j<<endl;
//	}
//	cout<<"VALUE: "<<ex[1]<<' '<<ex[2]<<' '<<dep1[1]<<' '<<dep1[2]<<endl;
	auto push=[&](int u,node b){
		if(b1[u].fr==b.fr||b2[u].fr==b.fr) return;
		if(b1[u].w<b.w){
			if(b1[u].c!=b.c) b2[u]=b1[u];
			b1[u]=b;
		}else if(b1[u].c!=b.c&&b2[u].w<b.w) b2[u]=b;
	};
	auto dfs1=[&](auto self,int u,int fa)->void{
		b1[u]=node(ex[u],col[u],u);b2[u]=node();ex[u]=-1e18;
		for(int v:vir[u])if(v!=fa){
			self(self,v,u);
			push(u,node(b1[v].w+dep2[v]-dep2[u],b1[v].c,b1[v].fr));
			push(u,node(b2[v].w+dep2[v]-dep2[u],b2[v].c,b2[v].fr));
		}
	};dfs1(dfs1,1,0);// 自下而上 
//	cout<<"FIRST"<<endl;
//	cout<<b1[1].w<<' '<<b1[1].c<<endl;
//	cout<<b1[2].w<<' '<<b1[2].c<<' '<<dep1[1]<<endl;
//	cout<<col[1]<<' '<<col[2]<<' '<<dep1[r]<<endl;
	auto dfs2=[&](auto self,int u,int fa)->void{
		for(int v:vir[u])if(v!=fa){
			push(v,node(b1[u].w+dep2[v]-dep2[u],b1[u].c,b1[u].fr));
			push(v,node(b2[u].w+dep2[v]-dep2[u],b2[u].c,b2[u].fr));
			self(self,v,u);
		}
		vir[u].clear();
	};dfs2(dfs2,1,0);// 自上而下 
//	cout<<b1[1].w<<' '<<b1[1].c<<endl;
//	cout<<b1[2].w<<' '<<b1[2].c<<' '<<dep1[1]<<endl;
//	cout<<col[1]<<' '<<col[2]<<' '<<dep1[r]<<endl;
	auto dfs3=[&](auto self,int u,int fa)->void{
		for(query q:que[u]){
//			cout<<"GO! "<<u<<' '<<q.v<<endl;
			if(u==r||b1[q.v].c!=col[u]) ans[q.id]=max(ans[q.id],dep1[u]+b1[q.v].w);
			if(u==r||b2[q.v].c!=col[u]) ans[q.id]=max(ans[q.id],dep1[u]+b2[q.v].w);
		} 
		for(edge e:edg1[u]) if(e.v!=fa&&!vis[e.v]) self(self,e.v,u);
	};dfs3(dfs3,r,0);
	for(edge e:edg1[r]) if(!vis[e.v]){
		tsiz=siz[e.v];son=0;
		get_size(e.v,0);get_size(son,0);
		dfz(son);
	}
}
int main(){
	ios::sync_with_stdio(false);
	memset(ex,-0x3f,sizeof(ex));
	cin>>n>>q;
	for(int i=1;i<n;i++){
		int u,v,w;cin>>u>>v>>w;
		edg1[u].push_back(edge(v,w));
		edg1[v].push_back(edge(u,w));
	}
	for(int i=1;i<n;i++){
		int u,v,w;cin>>u>>v>>w;
		edg2[u].push_back(edge(v,w));
		edg2[v].push_back(edge(u,w));
	}
	for(int i=1;i<=q;i++){
		int u,v;cin>>u>>v;
		que[u].push_back(query(v,i));
	} 
	dfs(1,0);T2.build();
//	cout<<"DEEP: "<<dep2[1]<<' '<<dep2[2]<<endl;
	maxx[0]=1e9;tsiz=n;
	get_size(1,0);get_size(son,0);dfz(son);
	for(int i=1;i<=q;i++) cout<<ans[i]<<endl;
}
/*
2 4
1 2 1
1 2 3
1 1
1 2
2 1
2 2
*/