using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Globalization;
using System.Diagnostics;
using static System.Console;
using Pair = System.Collections.Generic.KeyValuePair<int, int>;
//using System.Numerics;

class Program
{
    static void Main()
    {
        SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().solve();
        Out.Flush();
    }
    Scanner cin = new Scanner();
    Random rnd = new Random();
    Stopwatch sw = new Stopwatch();
    readonly int[] dd = { 0, 1, 0, -1, 0 };
    readonly int mod = 1000000007;
    readonly string alfa = "abcdefghijklmnopqrstuvwxyz";
    readonly string ALFA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    struct Edge : IComparable
    {
        public int to; public long cost;
        public Edge(int to, long cost)
        {
            this.to = to;
            this.cost = cost;
        }
        public int CompareTo(object obj)
        {
            return (int)(cost - ((Edge)obj).cost);
        }
    }
    int N;
    void solve()
    {
        N = cin.nextint;
        var D = Enumerable.Repeat(long.MaxValue, N).ToArray();
        var G = Enumerable.Range(0, N).Select(i => new List<Edge>()).ToArray();
        for (int i = 0; i < N - 1; i++)
        {
            var a = cin.nextint - 1;
            var b = cin.nextint - 1;
            var c = cin.nextint;
            G[a].Add(new Edge(b, c));
            G[b].Add(new Edge(a, c));
        }
        int T = cin.nextint;
        var Q = new PriorityQueue<Edge>();
        int K = cin.nextint - 1;
        Q.Enqueue(new Edge(K, 0));
        D[K] = 0;
        while (Q.Any())
        {
            var e = Q.Dequeue();
            var v = e.to;

            if (D[v] < -e.cost) continue;

            foreach (var gv in G[v])
            {
                if (D[gv.to] > D[v] + gv.cost)
                {
                    D[gv.to] = D[v] + gv.cost;
                    Q.Enqueue(new Edge(gv.to, -D[gv.to]));
                }
            }
        }
        for (int i = 0; i < T; i++)
        {
            var x = cin.nextint - 1;
            var y = cin.nextint - 1;
            WriteLine(D[x] + D[y]);
        }

        
        
    }

}
class PriorityQueue<T> where T : IComparable
{
    List<T> heap;
    int size;
    int Compare(T x, T y) { return y.CompareTo(x); }
    public PriorityQueue() { heap = new List<T>(); }

    public void Enqueue(T x)
    {
        heap.Add(x);
        int i = size++;

        while (i > 0)
        {
            int p = (i - 1) >> 1;

            if (Compare(heap[p], x) <= 0) break;

            heap[i] = heap[p];
            i = p;
        }
        heap[i] = x;
    }

    public T Dequeue()
    {
        T ret = heap[0];
        T x = heap[--size];

        int i = 0;
        while ((i << 1) + 1 < size)
        {
            int a = (i << 1) + 1;
            int b = (i << 1) + 2;

            if (b < size && Compare(heap[b], heap[a]) < 0)
                a = b;
            if (Compare(heap[a], x) >= 0)
                break;

            heap[i] = heap[a];
            i = a;
        }
        heap[i] = x;
        heap.RemoveAt(size);
        return ret;
    }

    public int Count { get { return size; } }

    public bool Any() { return size > 0; }

    public T Peek() { return heap[0]; }
}

class Scanner
{
    string[] s; int i;
    char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] scan { get { return ReadLine().Split(); } }
    public int[] scanint { get { return Array.ConvertAll(scan, int.Parse); } }
    public long[] scanlong { get { return Array.ConvertAll(scan, long.Parse); } }
    public double[] scandouble { get { return Array.ConvertAll(scan, double.Parse); } }
    public string next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return next;
        }
    }
    public int nextint { get { return int.Parse(next); } }
    public long nextlong { get { return long.Parse(next); } }
    public double nextdouble { get { return double.Parse(next); } }
}

Measured memory_bytes: 40096