#include<bits/stdc++.h>
#define ll long long
#define int ll
#define R register
using namespace std;
const int N=1e5+5;
int n;
namespace Tree1{
	int st[N][22],dep[N],cur,dfn[N],lg[N];
	struct edge{int u,v,w;}e[N<<1];
	int head[N],tot;
	inline void add(int u,int v,int w){e[++tot]={v,head[u],w},head[u]=tot;}
	namespace LCA{
		inline void dfs_lca(int u,int fa){
			dfn[u]=++cur;
			st[dfn[u]][0]=fa;
			for(R int i=head[u];i;i=e[i].v){
				int v=e[i].u;
				if(v==fa)continue;
				dep[v]=dep[u]+e[i].w;
				dfs_lca(v,u);
			}
		}
		inline int getmin(int x,int y){return dep[x]<dep[y]?x:y;}
		inline void work(){
			lg[0]=-1;for(R int i=1;i<=n;++i)lg[i]=lg[i>>1]+1;
			for(R int j=1;(1<<j)<=n;++j){
				for(R int i=1;i+(1<<j)-1<=n;++i){
					st[i][j]=getmin(st[i][j-1],st[i+(1<<j-1)][j-1]);
				}
			}
		}
		inline int lca(int u,int v){
			if(u==v)return u;
			if(dfn[u]>dfn[v])swap(u,v);
			int k=lg[dfn[v]-dfn[u]];
			return getmin(st[dfn[u]+1][k],st[dfn[v]-(1<<k)+1][k]);
		}
	}
	using namespace LCA;
	inline ll dist(int x,int y){return dep[x]+dep[y]-2*dep[lca(x,y)];}
	inline void clear(){
		for(R int i=1;i<=n;++i)head[i]=0;tot=0;cur=0;
	}
};
namespace Tree2{
	int st[N][22],dep[N],cur,dfn[N],lg[N],rt=1;
	struct edge{int u,v,w;}e[N<<1];
	int head[N],tot;
	inline void add(int u,int v,int w){e[++tot]={v,head[u],w},head[u]=tot;}
	namespace LCA{
		inline void dfs_lca(int u,int fa){
			dfn[u]=++cur;
			st[dfn[u]][0]=fa;
			for(R int i=head[u];i;i=e[i].v){
				int v=e[i].u;
				if(v==fa)continue;
				dep[v]=dep[u]+e[i].w;
				dfs_lca(v,u);
			}
		}
		inline int getmin(int x,int y){return dep[x]<dep[y]?x:y;}
		inline void work(){
			lg[0]=-1;for(R int i=1;i<=n;++i)lg[i]=lg[i>>1]+1;
			for(R int j=1;(1<<j)<=n;++j){
				for(R int i=1;i+(1<<j)-1<=n;++i){
					st[i][j]=getmin(st[i][j-1],st[i+(1<<j-1)][j-1]);
				}
			}
		}
		inline int lca(int u,int v){
			if(u==v)return u;
			if(dfn[u]>dfn[v])swap(u,v);
			int k=lg[dfn[v]-dfn[u]];
			return getmin(st[dfn[u]+1][k],st[dfn[v]-(1<<k)+1][k]);
		}
	}
	using namespace LCA;
	inline ll dist(int x,int y){return dep[x]+dep[y]+dep[rt]*2-2*dep[lca(x,rt)]-2*dep[lca(y,rt)]+Tree1::dist(x,y);}
	struct node{
		int x,y,dis;
		node(){x=y=0,dis=-1;}
		node(int u){x=y=u;dis=0;}
		node(int u,int v){x=u,y=v;dis=dist(u,v);}
	}f[N][2];
	struct node Max(node x,node y){return (x.dis<y.dis?y:x);}
	inline node operator+(node x,node y){
		if(x.dis==-1||y.dis==-1)return Max(x,y);
		return Max(Max(node(x.x,x.y),node(y.x,y.y)),Max(Max(node(x.y,y.x),node(x.y,y.y)),Max(node(x.x,y.x),node(x.x,y.y))));
	}
	inline void dfs1(int u,int fa){
		f[u][0]=node(u);
		for(R int i=head[u];i;i=e[i].v){
			int v=e[i].u;
			if(v==fa)continue;
			dfs1(v,u);
			f[u][0]=f[u][0]+f[v][0];
		}
	}
	node pre[N];
	inline void dfs2(int u,int fa){
		rt=u;int cnt=0;
		vector<int> son;
		for(R int i=head[u];i;i=e[i].v){
			int v=e[i].u;
			if(v==fa)continue;
			son.emplace_back(v);
			++cnt;pre[cnt]=pre[cnt-1]+f[v][0];
		}
		int cntt=0;node suf;
		for(R int i=cnt-1;i>=0;--i){
			int sn=son[i];
			rt=sn;
			++cntt;
			f[sn][1]=suf+pre[cnt-cntt]+f[u][1]+node(u);
			rt=u;
			suf=f[sn][0]+suf;
		}
		for(R int i=head[u];i;i=e[i].v){
			int v=e[i].u;
			if(v==fa)continue;
			dfs2(v,u);
		}
	}
	inline ll qry(int x,int y){
		rt=y;
		node D=f[y][0]+f[y][1];
		ll ls=dep[y]+dep[D.x]-dep[lca(y,D.x)]*2+Tree1::dist(x,D.x);
		ll rs=dep[y]+dep[D.y]-dep[lca(y,D.y)]*2+Tree1::dist(x,D.y);
		return max(ls,rs);
	}
	inline void clear(){
		for(R int i=1;i<=n;++i)head[i]=0,f[i][0]=f[i][1]=node();tot=0,cur=0;
		rt=1;
	}
};
inline void solve(){
	int q;
	cin>>n>>q;
	for(R int i=1;i<n;++i){
		int u,v,w;cin>>u>>v>>w;
		Tree1::add(u,v,w);
		Tree1::add(v,u,w);
	}
	for(R int i=1;i<n;++i){
		int u,v,w;cin>>u>>v>>w;
		Tree2::add(u,v,w);
		Tree2::add(v,u,w);
	}
	Tree1::dfs_lca(1,0);
	Tree2::dfs_lca(1,0);
	Tree1::work();
	Tree2::work();Tree2::dfs1(1,0);Tree2::dfs2(1,0);
	while(q--){
		int x,y;cin>>x>>y;cout<<Tree2::qry(x,y)<<'\n';
	}
	Tree1::clear();Tree2::clear();
}
signed main(){
	freopen("move.in","r",stdin);
	freopen("move.out","w",stdout);
	ios::sync_with_stdio(0);cin.tie(0),cout.tie(0);
	int _=1;while(_--)solve();
	return 0;
}