/**
 *    author  : 𝒌𝒚𝒐𝒎𝒖𝒌𝒚𝒐𝒎𝒖𝒑𝒖𝒓𝒊𝒏
 *    created : 2020-03-27 16:10:32
**/

#include <iostream>
#include <deque>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <complex>
#include <numeric>
#include <bitset>
#include <cassert>
#include <cctype>
#include <iomanip>
#include <random>
#include <utility>
#include <chrono>

using namespace std;

using int64 = long long;

template<class T> using binary_heap = std::priority_queue<T, std::vector<T>, std::greater<T>>;
template<class T> std::ostream& operator<<(std::ostream& os, const std::vector<T>& vec) { os << '{'; size_t n = vec.size(); for (size_t i = 0; i < n; ++i) { os << vec[i]; if (i != n - 1) os << ','; } os << '}'; return os; }
template<class T, class U> std::ostream& operator<<(std::ostream& os, const std::pair<T, U>& p) { return os << '{' << p.first << " " << p.second << '}'; }
template<class T, class U> std::ostream& operator<<(std::ostream& os, const std::map<T, U>& mp) { os << '{'; for (auto it = mp.begin(); it != mp.end(); ++it) { os << '{' << it->first << ':' << it->second << '}'; if (it != --mp.end()) os << ','; } os << '}'; return os; }
template<class T> std::ostream& operator<<(std::ostream& os, const std::set<T>& st) { os << '{'; for (auto it = st.begin(); it != st.end(); ++it) { os << *it; if (it != --st.end()) os << ','; } os << '}'; return os; }
template<class T> std::istream& operator>>(std::istream& is, std::vector<T>& vec) { size_t n = vec.size(); for (size_t i = 0; i < n; ++i) is >> vec[i]; return is; }

#define all(_) begin(_), end(_)
#define rall(_) rbegin(_), rend(_)

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__)
#else
#define debug(...) 1728
#endif

void debug_out() { std::cerr << '\n'; }

template <class Head, class... Tail>
void debug_out(Head&& head, Tail&&... tail) {
  std::cerr << head;
  if (sizeof...(Tail) != 0) std::cerr << ", ";
  debug_out(std::forward<Tail>(tail)...);
}

template <class T>
class Dijkstra {
 public:
  Dijkstra(int node_size) : node_size_(node_size) { Initialize(); }

  void Add_Edge(int from, int to, T cost) {
    graph_[from].push_back({to, cost});
  }

  void Solve(int source) {
    std::priority_queue<std::pair<T, int>, std::vector<std::pair<T, int>>,
                        std::greater<std::pair<T, int>>> pq;
    distance_[source] = 0;
    pq.push({0, source});

    while (!pq.empty()) {
      std::pair<T, int> top = pq.top();
      pq.pop();
      int v = top.second;
      if (distance_[v] < top.first) continue;
      for (const auto& e : graph_[v]) {
        if (distance_[e.to] > distance_[v] + e.cost) {
          distance_[e.to] = distance_[v] + e.cost;
          pq.push({distance_[e.to], e.to});
        }
      }
    }
  }

  T operator[](int to) const { return distance_[to]; }

 private:
  struct edge {
    int to;
    T cost;
  };
  int node_size_;
  std::vector<T> distance_;
  std::vector<std::vector<edge>> graph_;

  void Initialize() {
    distance_.assign(node_size_, std::numeric_limits<T>::max() / 2);
    graph_.resize(node_size_);
  }
};

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int n; cin >> n;
  Dijkstra<int64> dij(n);
  for (int i = 0; i < n - 1; ++i) {
    int a, b; int64 c; cin >> a >> b >> c; --a; --b;
    dij.Add_Edge(a, b, c);
    dij.Add_Edge(b, a, c);
  }

  int q, k; cin >> q >> k; --k;

  dij.Solve(k);

  while (q--) {
    int x, y; cin >> x >> y; --x; --y;
    cout << dij[x] + dij[y] << endl;
  }

  return 0;
}

Measured memory_bytes: 11120