#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=2010,M=201000;
ll g[N][N],te,ret[M],d[N];
int n,q,par[N],pw[N],pe[N];
VI ord;
vector<PII> e[N];
vector<array<int,3>> qr[N];
void dfs0(int u,int f,ll d,int rt) {
	g[rt][u]=d;
	for (auto [v,w]:e[u]) if (v!=f) {
		dfs0(v,u,d+w,rt);
	}
}

void gao(int u,int f) {
	ord.pb(u);
	for (auto [v,w]:e[u]) if (v!=f) {
		par[v]=u;
		pw[v]=w;
		gao(v,u);
	}
}
int main() {
	scanf("%d%d",&n,&q);
	rep(i,1,n) {
		int u,v,w;
		scanf("%d%d%d",&u,&v,&w);
		e[u].pb(mp(v,w));
		e[v].pb(mp(u,w));
		te+=w;
	}
	rep(i,1,n+1) dfs0(i,0,0,i);
	rep(i,0,q) {
		int s,k,t;
		scanf("%d%d%d",&s,&k,&t);
		ret[i]=-1;
		if (g[s][t]+g[t][k]==g[s][k]) {
			continue;
		}
		qr[s].pb({k,t,i});
	}
	rep(rt,1,n+1) {
		ord.clear();
		gao(rt,0);
		par[rt]=0;
		pw[rt]=0;
		d[rt]=0;
		for (auto [k,t,id]:qr[rt]) {
			rep(i,1,n+1) pe[i]=pw[i];
			int u=k;
			while (g[rt][u]+g[u][t]!=g[rt][t]) {
				pe[u]=-pw[u];
				u=par[u];
			}
			ll ans=0;
			rep(i,1,SZ(ord)) {
				int u=ord[i];
				d[u]=d[par[u]]+pe[u];
				//printf("%d %lld\n",u,d[u]);
				ans=max(ans,d[u]);
			}
			ret[id]=2*te-ans;
		}
	}
	rep(i,0,q) {
		if (ret[i]==-1) puts("impossible");
		else printf("%lld\n",ret[i]);
	}
}