#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
//#define int long long
using bll = boost::multiprecision::cpp_int;
using ll = long long;
//constexpr int INF = 1e9;//INT_MAX=(1<<31)-1=2147483647
constexpr ll INF = (ll)1e18;//(1LL<<63)-1=9223372036854775807
constexpr ll MOD = (ll)1e9 + 7;
constexpr double EPS = 1e-9;
constexpr int dx[4]={1,0,-1,0};
constexpr int dy[4]={0,1,0,-1};
#define p(var) std::cout<<var<<std::endl
#define PI (acos(-1))
#define rep(i, n)   for(ll i=0, i##_length=(n); i< i##_length; ++i)
#define repeq(i, n) for(ll i=1, i##_length=(n); i<=i##_length; ++i)
#define all(v) (v).begin(), (v).end()
#define uniq(v) (v).erase(unique((v).begin(), (v).end()), (v).end());
template<typename T> inline void pv(vector<T> v) { for(ll i=0, N=v.size(); i<N; i++) cout<< v[i] << (i==N-1 ? '\n' : ' '); }
template<typename T> inline T gcd(T a, T b) { return b ? gcd(b,a%b) : a; }
template<typename T> inline T lcm(T a, T b) { return a / gcd(a,  b) * b; }
template<typename T1, typename T2> inline T1 power(T1 x, T2 n){ return n ? power(x*x%MOD,n/2)*(n%2?x:1)%MOD : 1; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
template<typename T> class dvector : public std::vector<T> {
public:
	dvector() : std::vector<T>() {}
	explicit dvector(size_t n, const T& value = T()) : std::vector<T>(n,value) {}
	dvector(const std::vector<T>& v) : std::vector<T>(v) {}
	dvector(const std::initializer_list<T> il) : std::vector<T>(il) {}
	dvector(const typename std::vector<T>::iterator first, const typename std::vector<T>::iterator last) : std::vector<T>(first, last) {}
	dvector(const std::string::iterator first, const std::string::iterator last) : std::vector<T>(first, last) {}
	T& operator[](size_t n) { return this->at(n); }
	const T& operator[](size_t n) const { return this->at(n); }
};
class dbool{
public:
	dbool() : boolvalue(false) {}
	dbool(bool b) : boolvalue(b) {}
	dbool(const dbool &b) : boolvalue(b.boolvalue) {}
	operator bool&() { return boolvalue; }
	operator const bool&() const { return boolvalue; }
private:
	bool boolvalue;
};
template<typename T1, typename T2> ostream& operator<<(ostream& s, pair<T1, T2>& p) {return s << "(" << p.first << ", " << p.second << ")";}
template<typename T> ostream& operator<<(ostream& s, dvector<T>& v) {
	for (int i = 0, len = v.size(); i < len; ++i){ s << v[i]; if (i < len - 1) s << "\t"; } return s; }
template<typename T> ostream& operator<<(ostream& s, dvector< dvector<T> >& vv) {
	for (int i = 0, len = vv.size(); i < len; ++i){ s << vv[i] << endl; } return s; }
template<typename T1, typename T2> ostream& operator<<(ostream& s, map<T1, T2>& m) {
	s << "{" << endl; for (auto itr = m.begin(); itr != m.end(); ++itr){ s << "\t" << (*itr).first << " : " << (*itr).second << endl; } s << "}" << endl; return s; }
template<typename T> ostream& operator<<(ostream& s, set<T>& se) {
	s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}" << endl; return s; }
template<typename T> ostream& operator<<(ostream& s, multiset<T>& se) {
	s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}" << endl; return s; }
#ifdef LOCAL_DEV
	#define debug(var) std::cout<<#var" = "<<var<<std::endl
#else
	#define debug(var)
#endif
#ifdef LOCAL_TEST
	#define vector dvector
	#define bool dbool
#endif

/*-----8<-----8<-----*/

class Edge {
public:
	ll from,to,cost;
	Edge() {}
	Edge(ll from, ll to, ll cost) : from(from), to(to), cost(cost) {}
};
ostream& operator<<(ostream& s, const Edge& e) {
	s << "{ " << e.from << " -> " << e.to << ", " << e.cost << " }";
	return s;
}

/*
最小共通祖先(Doubling-Lowest-Common-Ancestor)
DoublingLowestCommonAncestor(g):= 木 g で初期化する。
build():= 構築する。
query(u, v):= 頂点 u と v の最小共通祖先を返す。
 */
template< typename G >
class DoublingLowestCommonAncestor {
public:
	const G &g;
	vector< int > depth;//depth[v]=根からvまでの距離
	const int LOG;
	vector< vector< int > > table;

	DoublingLowestCommonAncestor(const G &g) : g(g), depth(g.size()), LOG(32 - __builtin_clz(g.size())) {
		table.assign(LOG, vector< int >(g.size(), -1));
	}

	void dfs(int idx, int par, int d) {
		table[0][idx] = par;
		depth[idx] = d;
		for(auto &to : g[idx]) {
			if(to != par) dfs(to, idx, d + 1);
		}
	}

	void build() {
		dfs(0, -1, 0);
		for(int k = 0; k + 1 < LOG; k++) {
			for(int i = 0,tablesize = table[k].size(); i < tablesize; i++) {
				if(table[k][i] == -1) table[k + 1][i] = -1;
				else table[k + 1][i] = table[k][table[k][i]];
			}
		}
	}

	int query(int u, int v) {
		if(depth[u] > depth[v]) swap(u, v);
		for(int i = LOG - 1; i >= 0; i--) {
			if(((depth[v] - depth[u]) >> i) & 1) v = table[i][v];
		}
		if(u == v) return u;
		for(int i = LOG - 1; i >= 0; i--) {
			if(table[i][u] != table[i][v]) {
				u = table[i][u];
				v = table[i][v];
			}
		}
		return table[0][u];
	}
};

////


void dfs(vector<vector<Edge>> &g, vector<ll> &costs,ll v,ll p){

	for(Edge nextv:g[v]){
		if(nextv.to==p)continue;
		costs[nextv.to]=costs[v]+nextv.cost;
		dfs(g,costs,nextv.to,v);
	}

}

signed main() {
	//ABC014D

	//cinから受付
	//N:ノードの数、0〜(node_size-1)がノード番号として定義される
	//M:与えられるEdgeの数
	ll N,M;
	cin >> N;
	M=N-1;
	vector<vector<ll>> g(N);
	vector<vector<Edge>> eg(N);
	for (ll i=0; i<M; i++) {
		ll from,to,cost;
		cin >> from >> to >> cost;
		from--;to--;
		g[from].push_back(to);
		g[to].push_back(from);
		Edge e1(from,to,cost);
		Edge e2(to,from,cost);
		eg[from].push_back(e1);
		eg[to].push_back(e2);
	}

	ll Q,K;
	cin>>Q>>K;
	K--;

	DoublingLowestCommonAncestor< vector<vector<ll>> > lca(g);
	lca.build();
	
	vector<ll> costs(N,0);
	dfs(eg,costs,0,-1);

	vector<ll> anslist(Q,0);
	rep(i,Q){
		ll x,y;
		cin>>x>>y;
		x--;y--;
		ll lcaxy=lca.query(x, y);
		ll lcakx=lca.query(K, x);
		ll lcaky=lca.query(K, y);
		ll ans=0;
		if(lcaxy==K){//1
			ans=costs[x]+costs[y]-2*costs[K];
		}else if(lcakx==K || lcaky==K){//2
			if(lcakx==x || lcaky==y){//2A
				ans=abs(costs[x]-costs[y]);
			}else{//2B
				if(lcakx==lcaky){
					ans=costs[x]+costs[y]-2*costs[K];
				}else{
					ans=costs[x]+costs[y]-2*costs[lcaxy];
				}
			}
		}else if(lcakx==lcaky){//3
			ans=costs[x]+costs[y]+2*costs[K]-4*costs[lcakx];
		}else if(lcaxy==lcakx){//4A
			ans=costs[K]+costs[y]-2*costs[lcaky]  +costs[K]-costs[lcaxy]  +costs[x]-costs[lcaxy];
		}else if(lcaxy==lcaky){//4B
			ans=costs[K]+costs[x]-2*costs[lcakx]  +costs[K]-costs[lcaxy]  +costs[y]-costs[lcaxy];
		}else{
			exit(1);
		}
		
		anslist[i]=ans;
	}

	rep(i,Q)p(anslist[i]);
	return 0;
}


Measured memory_bytes: 32248