#pragma GCC optimize("Ofast", "unroll-loops", "fast-math", "no-stack-protector")
#pragma GCC target("avx", "avx2", "sse", "sse3", "sse4.1")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define all(x) (x).begin(), (x).end()
template <class T1, class T2>
bool cmin(T1& x, const T2& y) {
  if (y < x) {
    x = y;
    return 1;
  }
  return 0;
}
template <class T1, class T2>
bool cmax(T1& x, const T2& y) {
  if (x < y) {
    x = y;
    return 1;
  }
  return 0;
}
struct Q {
  int v, w;
};
const int N = 2e3 + 5;
vector<Q> e[N];
ll dis[N][N], dis2[N][N * 2];
int eular[N][N * 2], f[N][N];
int cur, id;
int s, k, t;
int sts[N], stt[N], tps, tpt, lcas[N], lcat[N], ed[N];
void dfs(int u) {
  ed[u] = 1;
  eular[cur][id++] = u;
  for (auto [v, w] : e[u])
    if (!ed[v]) {
      f[cur][v] = u;
      dis[cur][v] = dis[cur][u] + w;
      dfs(v);
    }
  eular[cur][id++] = -u;
  ed[u] = 0;
}
/*void dfs2(int u) {
  ed[u] = 1;
  if (dis[s][k] == dis[s][u] + dis[k][u]) sts[++tps] = u;
  if (dis[s][t] == dis[s][u] + dis[t][u]) stt[++tpt] = u;
  lcas[u] = sts[tps];
  lcat[u] = stt[tpt];
  for (auto [v, w] : e[u])
    if (!ed[v]) dfs2(v);
  ed[u] = 0;
  if (sts[tps] == u) --tps;
  if (stt[tpt] == u) --tpt;
}*/
mt19937 rnd(345);
int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, m, q, i, j;
  cin >> n >> m;
  ll base = 0;
  for (i = 1; i < n; i++) {
    int u, v, w;
    // u = i;
    // v = i + 1;
    // w = 1;
    // u = rnd() % i + 1;
    // v = i + 1;
    cin >> u >> v >> w;
    base += w;
    e[u].push_back({v, w});
    e[v].push_back({u, w});
  }
  base <<= 1;
  for (i = 1; i <= n; i++) {
    id = 0, dfs(cur = i);
    for (j = 0; j < n * 2; j++) dis2[i][j] = dis[i][eular[i][j]];
  }
  map<array<int, 3>, ll> res;
  while (m--) {
    ll ans = 1e18;
    cin >> s >> k >> t;
    if (dis[s][t] + dis[t][k] == dis[s][k]) {
      cout << "impossible\n";
      continue;
    }
    if (res.count({s, k, t})) {
      cout << res[{s, k, t}] << '\n';
      continue;
    }
    tps = tpt = 0;
    int *nfd = eular[s], *fa = f[s];
    ll *ds = dis[s], *dt = dis[t], *dk = dis[k], *ds2 = dis2[s];
    ll c1 = ds[k], c2 = ds[t];
    for (i = 0; i < n * 2; i++, ++ds2) {
      int u = nfd[i];
      if (u > 0) {
        if (c1 == *ds2 + dk[u]) tps = u;
        if (c2 == *ds2 + dt[u]) tpt = u;
        cmin(ans, max(0ll, ds[tps] - ds[tpt]) * 2 - *ds2);
      } else {
        if (tps == -u) tps = fa[tps];
        if (tpt == -u) tpt = fa[tpt];
      }
    }
    cout << (res[{s, k, t}] = base + ans) << '\n';
  }
}