#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
#include <bits/stdc++.h>
int getInt() {
	int res = 0;
	char c = getchar();
	while(c < '0' || c > '9'){
		c = getchar();
	}
	while(c >= '0' && c <= '9'){
		res = res * 10 + (c - '0');
		c = getchar();
	}
	return res;
}
using namespace std;
#define shit shittttttt
const int N = 2010;
const int Q = 2e5+10;

typedef long long ll;
typedef pair<int,ll> pil;

int n, q;
ll tot_w;
vector<pil> g[N];
int id, l[N][N], r[N][N];
ll dep[N][N];
int mom[N][N];
int s, k, t;


inline bool anc(int u, int v) {
	return l[s][u] <= l[s][v] && r[s][v] <= r[s][u];
}
void dfs(int u, int p, ll d) {
	mom[s][u]=p;
	dep[s][u] = d;
	++id;
	l[s][u] = id;
	for (auto [v, w]: g[u]) if (v != p) {
		dfs(v, u, d + w);
	}
	r[s][u] = id;
}
vector<int> leaf[N];
ll d_proj_k[N], d_proj_t[N];
int qu[N];

ll solve() {
	//id = 0;
	//dfs(s, -1, 0);
	if (anc(t, k)) return -1;
	ll res = tot_w * 2ll;
	//dfs2(s, -1, -1, -1, res);
	
	int ql = 0, qr = 0;
	qu[qr++] = s;
	//dep[s] = 0;
	while (ql < qr) {
		int u = qu[ql++];
		d_proj_k[u] = d_proj_k[mom[s][u]];
		d_proj_t[u] = d_proj_t[mom[s][u]];
		if (anc(u, k)) {
			d_proj_k[u] = dep[s][u];
		}
		if (anc(u, t)) {
			d_proj_t[u] = dep[s][u];
		}
		for (auto [v, w]: g[u]) if (v != mom[s][u]) {
			qu[qr++] = v;
		}
	}
	for(auto i:leaf[s]){
		ll tmp = tot_w * 2ll - dep[s][i];
		if (d_proj_k[i] > d_proj_t[i])
			tmp += 2ll * (d_proj_k[i] - d_proj_t[i]);
		res = min(res, tmp);
	}
	
	for(int i=0;i<qr;i++)d_proj_k[i]=d_proj_t[i]=-1;
	return res;
}
map<pair<int,pair<int,int>>,long long > dic;

int main() {
	n = getInt();
	q = getInt();
	for (int i = 0; i < n-1; ++i) {
		int u, v, w;
		u = getInt();
		v = getInt();
		w = getInt();
		g[u].push_back({v, w});
		g[v].push_back({u, w});
		tot_w += w;
	}
	for (s = 1; s <= n; ++s) {
		id = 0;
		dfs(s, -1, 0);
		leaf[s].clear();
		for (int i = 1; i <= n; ++i) if (i != s && g[i].size() == 1) leaf[s].push_back(i);

	}
	fill(d_proj_k, d_proj_k + n + 1, -1);
	fill(d_proj_t, d_proj_t + n + 1, -1);
	while (q--) {
		
		s = getInt();
		k = getInt();
		t = getInt();
		ll ans;
    auto tt=make_pair(s,make_pair(k,t));
    if (dic.find(tt)!=dic.end())ans=dic[tt];
else ans = solve();
		if (ans == -1) puts("impossible");
		else printf("%lld\n", ans);
	}
}