#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#define ff first
#define ss second
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int SZ = 2020;

int n, q;
vector<pii> g[SZ];

int par[SZ], col[SZ];
ll dep[SZ], mx[SZ];
void dfs(int p, int v) {
	mx[v] = dep[v];
	for (auto [w, x] : g[v]) if (p != x) {
		dep[x] = dep[v] + w;
		par[x] = v;
		dfs(v, x);
		mx[v] = max(mx[v], mx[x]);
	}
}

int main() {
	cin.tie(0); ios_base::sync_with_stdio(0);
	cin >> n >> q;
	ll tot = 0;
	for (int i = 0; i < n - 1; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		g[u].push_back({w, v});
		g[v].push_back({w, u});
		tot += w;
	}
	
	while (q--) {
		int s, k, t;
		cin >> s >> k >> t;
		dep[s] = 0;
		dfs(-1, s);
		for (int v = 1; v <= n; v++) col[v] = 0;
		for (int v = t; ; v = par[v]) {
			col[v] = 1;
			if (v == s) break;
		}
		if (col[k]) {
			cout << 2 * tot - mx[s] << '\n';
			continue;
		}
		int l = k;
		while (!col[l]) {
			col[l] = 2;
			l = par[l];
		}
		if (l == t) {
			cout << "impossible\n";
			continue;
		}
		ll ans = 1e18;
		for (int v = t; ; v = par[v]) {
			ans = min(ans, 2 * tot - dep[v]);
			for (auto [w, x] : g[v]) if (x != par[v] && !col[x]) {
				ans = min(ans, 2 * tot - mx[x]);
			}
			if (v == s) break;
		}
		for (int v = k; col[v] == 2; v = par[v]) {
			ans = min(ans, 2 * tot - dep[v] + 2 * (dep[v] - dep[l]));
			for (auto [w, x] : g[v]) if (x != par[v] && !col[x]) {
				ans = min(ans, 2 * tot - mx[x] + 2 * (dep[v] - dep[l]));
			}
		}
		cout << ans << '\n';
	}
}