import java.util.*
import kotlin.*

import java.io.InputStream
import java.lang.NumberFormatException
import java.lang.StringBuilder


fun main(args: Array<String>) {
    Program().solve()
}

class Program {
    fun solve() {
        val sc = FastScanner()
        val n = sc.nextInt()

        val abc = Array(n - 1) { Triple(sc.nextInt() - 1, sc.nextInt() - 1, sc.nextLong()) }
        val q = sc.nextInt()
        val k = sc.nextInt() - 1

        val t = Tree(n, k)
        for (i in 0 until n - 1) {
            t.addEdge(abc[i].first, abc[i].second, abc[i].third)
        }
        t.build()
        val sb = StringBuilder()
        for (i in 0 until q) {
            val x = sc.nextInt() - 1
            val y = sc.nextInt() - 1

            sb.appendln((t.getDistance(x) + t.getDistance(y)).toString())
        }

        println(sb.toString())
    }
}

class Tree(private val v: Int, private val root: Int) {
    private val edges = Array(v) { mutableListOf<Edge>() }
    private val dist = Array(v) { -1L }

    fun addEdge(f: Int, t: Int, c: Long) {
        edges[f].add(Edge(t, c))
        edges[t].add(Edge(f, c))
    }

    fun build() {
        val stack = Array(v) { -1 }
        val index = Array(v) { -1 }
        var ptr = 0
        var s = 0L
        stack[0] = root

        while (ptr >= 0) {
            do {
                index[ptr]++
                // 次のnodeが一個上のnodeならもう一回
            } while (ptr > 0 && index[ptr] < edges[stack[ptr]].size && stack[ptr - 1] == edges[stack[ptr]][index[ptr]].to);
            if (index[ptr] >= edges[stack[ptr]].size) {
                // 終わってたら
                index[ptr] = -1
                dist[stack[ptr]] = s
                ptr--
                if (ptr >= 0) {
                    s -= edges[stack[ptr]][index[ptr]].cost
                }
            } else {
                stack[ptr + 1] = edges[stack[ptr]][index[ptr]].to
                s += edges[stack[ptr]][index[ptr]].cost
                ptr++
            }
        }
    }

    fun getDistance(i: Int) = dist[i]

    data class Edge(val to: Int, val cost: Long)
}


class FastScanner {
    companion object {
        val input: InputStream = System.`in`
        val buffer = ByteArray(1024) { 0 }
        fun isPrintableChar(c: Int): Boolean = c in 33..126
    }

    var ptr = 0
    var buflen = 0
    private fun hasNextByte(): Boolean {
        if (ptr < buflen) {
            return true
        } else {
            ptr = 0
            buflen = input.read(buffer)
            if (buflen <= 0) {
                return false
            }
        }
        return true
    }

    private fun readByte(): Int = if (hasNextByte()) buffer[ptr++].toInt() else -1

    private fun skipUnprintable() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr].toInt())) ptr++
    }

    fun hasNext(): Boolean {
        skipUnprintable()
        return hasNextByte()
    }

    fun next(): String {
        if (!hasNext()) throw NoSuchElementException()
        val sb = StringBuilder()
        var b = readByte()
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b)
            b = readByte()
        }
        return sb.toString()
    }

    fun nextInt(): Int {
        if (!hasNext()) throw NoSuchElementException()
        var n = 0
        var b = readByte()
        // '-' = 45
        val minus = b == 45
        if (minus) {
            b = readByte()
        }

        // '0' = 48 '9' = 57
        if (b !in 48..57) {
            throw NumberFormatException()
        }

        while (true) {
            if (b in 48..57) {
                n *= 10
                n += b - 48
            } else if (b == -1 || !isPrintableChar(b)) {
                return if (minus) -n else n
            } else {
                throw NumberFormatException()
            }
            b = readByte()
        }
    }

    fun nextLong(): Long {
        if (!hasNext()) throw NoSuchElementException()
        var n = 0L
        var b = readByte()
        // '-' = 45
        val minus = b == 45
        if (minus) {
            b = readByte()
        }

        // '0' = 48 '9' = 57
        if (b !in 48..57) {
            throw NumberFormatException()
        }

        while (true) {
            if (b in 48..57) {
                n *= 10
                n += b - 48
            } else if (b == -1 || !isPrintableChar(b)) {
                return if (minus) -n else n
            } else {
                throw NumberFormatException()
            }
            b = readByte()
        }
    }

    fun nextDouble(): Double = next().toDouble()
}


Measured memory_bytes: 84748