#include<bits/stdc++.h>
using namespace std;

int n,q,t1,t2,h,ans[100001];
bool visited[100001]={false};
vector<pair<int,int> > al[100001];

int r(int a, int b){
    visited[a]=true;
    ans[a]=b;
    for(int i=0;i<al[a].size();i++){
        if(!visited[al[a][i].first])r(al[a][i].first,b+al[a][i].second);
    }
}

int main(){
    ios::sync_with_stdio(0);
    cin >> n;
    for(int i=1;i<n;i++){
        cin >> t1 >> t2 >> h;
        al[t1].push_back(make_pair(t2,h));
        al[t2].push_back(make_pair(t1,-h));
    }
    r(1,1);
    cin >> q;
    while(q--){
        cin >> t1 >> t2;
        cout << ans[t2]-ans[t1]<<"\n";
    }
    return 0;
}