#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
struct node
{
	ll x,w;
	node(ll nx=0,ll nw=0){x=nx;w=nw;}
};


template<typename T> void read(T &x){
    x = 0;char ch = getchar();ll f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}
template<typename T> void write(T x) {
    if(x > 9) write(x/10);
    putchar(x%10 + '0');
}

vector<node>se[2048];
vector<int>s[2048];
ll dep[2048][2048],mx[2048];
int depi[2048][2048],vis[2048];
int dfn[2048][2048],ed[2048][2048];
int f[2048][12][2048],fr[2048];
int n,q,st,k,t,cnt=0,rt,c;
ll sum=0,ans=0;
int fa(int a,int b)
{
	if(depi[rt][a]>depi[rt][b])swap(a,b);
	for(int i=11;i>=0;i--)if(depi[rt][f[rt][i][b]]>=depi[rt][a])b=f[rt][i][b];
	if(a==b)return a;
	for(int i=11;i>=0;i--)if(f[rt][i][a]!=f[rt][i][b])a=f[rt][i][a],b=f[rt][i][b];
	return f[rt][0][a];
}
void dfs(int p,int ff)
{
	f[rt][0][p]=ff;
	dfn[rt][p]=ed[rt][p]=++cnt;
	for(int i=0;i<se[p].size();i++)
	{
		node v=se[p][i];
		if(v.x==ff)continue;
		dep[rt][v.x]=dep[rt][p]+v.w;
		depi[rt][v.x]=depi[rt][p]+1;
		dfs(v.x,p);
		ed[rt][p]=ed[rt][v.x];
	}
}
void dfs2(int p,int ff)
{
	fr[p]=fr[ff];
	if(vis[p])fr[p]=p;
	if(fr[p]==0)ans=min(ans,sum-dep[rt][p]);
	else
	{
		ans=min(ans,sum-dep[rt][p]+2ll*(dep[rt][fr[p]]-dep[rt][c]));
	}
	for(int i=0;i<s[p].size();i++)
		{
			int v=s[p][i];
			if(v==ff)continue;
			//dep[rt][v.x]=dep[rt][p]+v.w;
			//depi[rt][v.x]=depi[rt][p]+1;
			dfs2(v,p);
			//ed[rt][p]=ed[rt][v.x];
		}
}
int main()
{
	read(n, q);
	for(int i=1;i<n;i++)
	{
		int x,y,z;
		read(x, y, z);
		sum+=z;
		se[x].push_back(node(y,z));
		se[y].push_back(node(x,z));
		s[x].push_back(y);
		s[y].push_back(x);
	}
	sum=2ll*sum;
	for(int i=1;i<=n;i++)
	{
		cnt=0;rt=i;
		dep[i][i]=0;
		depi[i][i]=0;
		//f[i][0][i]=i;
		dfs(i,i);
		for(int j=1;j<12;j++)for(int k=1;k<=n;k++)f[i][j][k]=f[i][j-1][f[i][j-1][k]];
		for(int j=1;j<=n;j++)mx[rt]=max(mx[rt],dep[rt][j]);
	}
	for(int i=1;i<=q;i++)
	{
		read(st, k, t);
		rt=st;
		c=fa(k,t);
		if(c==k)write(sum-mx[st]), putchar('\n');
		else if(c==t)printf("impossible\n");
		else
		{
			memset(vis,0,sizeof(vis));
			for(int j=k;j!=c;j=f[rt][0][j])vis[j]=1;
			ans=sum;
			fr[st]=0;
			dfs2(rt,0);
			write(ans), putchar('\n');
		}
	}
	return 0;
}