#include<bits/stdc++.h>
using namespace std;
vector<pair<int, int>> G[500007];
int up[500007][19], maks[500007][19];
int pre[500007], pos[500007], pr, po;
void DFS(int a, int vater){
  pre[a] = ++pr;
  up[a][0] = vater;
  for(int i = 1;i < 19;i++){
    up[a][i] = up[up[a][i - 1]][i - 1];
    maks[a][i] = max(maks[a][i - 1], maks[up[a][i - 1]][i - 1]);
  }
  for(auto i : G[a])
    if(i.first != vater){
      maks[i.first][0] = i.second;
      DFS(i.first, a);
    }
  pos[a] = ++po;
}
bool ancestor(int u, int v){
  return pre[u] <= pre[v] && pos[u] >= pos[v];
}
int LCA(int u, int v){
  if(ancestor(u, v))
    return u;
  if(ancestor(v, u))
    return v;
  for(int i = 18;i >= 0;i--)
    if(ancestor(up[u][i], v))
      u = up[u][i];
  return up[u][0];
}
int Maks(int a, int k){
  int m = -INT_MAX;
  for(int i = 18;i >= 0;i--){
    if(!ancestor(k, up[a][i]))
      continue;
    m = max(m, maks[a][i]);
    a = up[a][i];
  }
  return m;
}
int main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, a, b;
  cin >> n;
  for(int i = 1, c;i < n;i++){
    cin >> a >> b >> c;
    G[a].emplace_back(b, c);
    G[b].emplace_back(a, c);
  }
  DFS(1, 1);
  while(cin >> a){
    if(a == -1)
      break;
    cin >> b;
    if(a == b){
      cout << 0;
      continue;
    }
    int k = LCA(a, b);
    cout << max(Maks(a, k), Maks(b, k)) << '\n';
  }
}