using System;
using System.Collections.Generic;
using System.Linq;

public class PriorityQueue<TKey, TValue>
{
    SortedDictionary<TKey, HashSet<TValue>> dict = new SortedDictionary<TKey, HashSet<TValue>>();
    Dictionary<TValue, TKey> rDict = new Dictionary<TValue, TKey>();
    int count = 0;

    public int Count
    {
        get
        {
            return count;
        }
    }

    public void Enqueue(TKey key, TValue value)
    {
        if (!dict.ContainsKey(key))
        {
            dict[key] = new HashSet<TValue>();
        }

        dict[key].Add(value);
        rDict[value] = key;
        count++;
    }

    public KeyValuePair<TKey, TValue> Dequeue()
    {
        var queue = dict.First();
        if (queue.Value.Count <= 1)
        {
            dict.Remove(queue.Key);
        }

        var val = queue.Value.First();
        queue.Value.Remove(val);
        count--;
        rDict.Remove(val);
        return new KeyValuePair<TKey, TValue>(queue.Key, val);
    }

    public KeyValuePair<TKey, TValue> Peek()
    {
        var queue = dict.First();
        var val = queue.Value.First();
        return new KeyValuePair<TKey, TValue>(queue.Key, val);
    }

    public void ChangePriority(TKey newKey, TValue value)
    {
        ChangePriority(rDict[value], newKey, value);
    }

    public void ChangePriority(TKey prevKey, TKey newKey, TValue value)
    {
        var set = dict[prevKey];
        set.Remove(value);
        if (set.Count == 0)
        {
            dict.Remove(prevKey);
        }
        count--;

        Enqueue(newKey, value);
    }

    public bool ContainsValue(TValue val)
    {
        return rDict.ContainsKey(val);
    }
}

class Solution
{
    static long[] Dijkstra(List<Tuple<int, int>>[] link, int k)
    {
        var n = link.Length - 1;
        var d = Enumerable.Repeat(long.MaxValue, n + 1).ToArray();
        d[k] = 0;
        var q = new PriorityQueue<long, int>();
        q.Enqueue(0, k);

        while (q.Count > 0)
        {
            var u = q.Dequeue();
            foreach (var nei in link[u.Value])
            {
                var v = nei.Item1;
                var len = nei.Item2;
                if (d[v] > d[u.Value] + len)
                {
                    d[v] = d[u.Value] + len;
                    if (q.ContainsValue(v))
                    {
                        q.ChangePriority(d[v], v);
                    }
                    else
                    {
                        q.Enqueue(d[v], v);
                    }
                }
            }
        }

        return d;
    }

    static void Main()
    {
        var n = int.Parse(Console.ReadLine());
        var link = Enumerable.Range(0, n + 1).Select(_ => new List<Tuple<int, int>>()).ToArray();
        for (int i = 0; i < n - 1; i++)
        {
            var v = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            link[v[0]].Add(Tuple.Create(v[1], v[2]));
            link[v[1]].Add(Tuple.Create(v[0], v[2]));
        }

        var vals = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        var q = vals[0];
        var k = vals[1];
        var query = new int[q][];
        for (int i = 0; i < q; i++)
        {
            query[i] = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        }

        var d = Dijkstra(link, k);

        foreach (var que in query)
        {
            Console.WriteLine($"{d[que[0]] + d[que[1]]}");
        }
    }
}

Measured memory_bytes: 75132