#include<bits/stdc++.h>
using namespace std;
int n, m;
const int N = 1e5 + 5;
const int MAXLOG = 18;
vector<array<int, 2>> e[N];
int mx2[N], dist[N];
array<int, 2> mx1[N];
int dp[N][20];
int depth[N];

void dfs(int u, int parent) {
  dp[u][0] = parent;
  depth[u] = depth[parent] + 1;
  for (auto [v,w] : e[u]) {
      if (v == parent) continue; // 不往回走
      dfs(v, u);
  }
}

void build_lca(int n) {
  for (int k = 1; k <= MAXLOG; k++) {
      for (int u = 1; u <= n; u++) {
          int ancestor = dp[u][k - 1];      
          dp[u][k] = dp[ancestor][k - 1];   
      }
  }
}

int lca(int u, int v) {
  if (depth[u] < depth[v]) swap(u, v); 
  int diff = depth[u] - depth[v];
  for (int k = 0; k <= MAXLOG; k++) {
      if (diff & (1 << k)) {
          u = dp[u][k];
      }
  }
  if (u == v) return u;
  for (int k = MAXLOG; k >= 0; k--) {
      if (dp[u][k] != dp[v][k]) {
          u = dp[u][k];
          v = dp[v][k];
      }
  }
  return dp[u][0];
}
void dfs0(int u, int fa) {
  vector<int> vals;
  mx1[u][0] = 0;
  mx1[u][1] = -1;// 最大值和次大值
  for (auto [v, w] : e[u]) {
    if (v == fa)continue;
    dist[v] = dist[u] + w;
    dfs0(v, u);
    vals.push_back(mx1[v][0] + w);
  }
  int sz = vals.size();
  if (sz == 0)return ;
  sort(vals.begin(), vals.end());
  mx1[u][0] = vals[sz - 1];
  if (sz >= 2)mx1[u][1] = vals[sz - 2];
}
void dfs1(int u, int fa, int up_mx) {
  mx2[u] = up_mx;
  vector<int> vals;
  for (auto [v, w] : e[u]) {
    if (v == fa)continue;
    vals.push_back(mx1[v][0]);
  }
  sort(vals.begin(), vals.end());
  int sz = vals.size();
  for (auto [v, w] : e[u]) {
    if (v == fa)continue;
    int mx = up_mx + w;
    for (int i = sz - 1; i >= max(sz - 2, 0); i--) {
      if (vals[i] != mx1[v][0]) {
        mx = max(mx, vals[i] + w);
      }
    }
    dfs1(v, u, mx);
  }
}
signed main () {
  cin >> n >> m;
  for (int i = 1; i <= n - 1; i++) {
    int u, v, c;
    cin >> u >> v >> c;
    e[u].push_back({v, c});
    e[v].push_back({u, c});
  }
  dfs(1, 0);
  dfs0(1, 0);
  dfs1(1, 0, 0);
  build_lca(n);
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    int fa = lca(x, y);
    int dis = dist[x] + dist[y] - 2 * dist[fa];
    int ans = 0;
    if (x == y) {
      if (mx2[x] == 0) {
        ans = mx1[x][0] + (mx1[x][1] == -1 ? 0 : mx1[x][1]);
      }
      else {
        ans = max(mx2[x] + mx1[x][0], mx1[x][0] + mx1[x][1]);
      }
    }
    else if (fa == x || fa == y) {
      if (depth[x] > depth[y])swap(x, y);
      ans = dis + mx2[x] + mx1[y][0];
      for (auto [v, w] : e[x]) {
        if (v == dp[x][0])continue;
        if (lca(v, y) == x) {
          ans = max(ans, dis + mx1[v][0] + w + mx1[y][0]);
        }
      }
    }
    else {
      ans = dis + mx1[x][0] + mx1[y][0];
    }
    cout << ans << endl;
  }
  return 0;
}