#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i,n) for (int i=0;i<(int)(n);i++)
#define codefor int test;scanf("%d",&test);while(test--)
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define yn(ans) if(ans)printf("Yes\n");else printf("No\n")
#define YN(ans) if(ans)printf("YES\n");else printf("NO\n")
#define vector1d(type,name,...) vector<type>name(__VA_ARGS__)
#define vector2d(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
const int MOD=1000000007;
//入力系
void scan(int& a){scanf("%d",&a);}
void scan(long long& a){scanf("%lld",&a);}
template<class T> void scan(T& a){cin>>a;}
template<class T> void scan(vector<T>& vec){for(auto&& it:vec)scan(it);}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){scan(head);in(tail...);}
//出力系
void print(const int& a){printf("%d",a);}
void print(const long long& a){printf("%lld",a);}
void print(const double& a){printf("%.15lf",a);}
template<class T> void print(const T& a){cout<<a;}
template<class T> void print(const vector<T>& vec){if(vec.empty())return;print(vec[0]);for(auto it=vec.begin();++it!= vec.end();){putchar(' ');print(*it);}}
void out(){putchar('\n');}
template<class T> void out(const T& t){print(t);putchar('\n');}
template <class Head, class... Tail> void out(const Head& head,const Tail&... tail){print(head);putchar(' ');out(tail...);}
//デバッグ系
template<class T> void dprint(const T& a){cerr<<a;}
template<class T> void dprint(const vector<T>& vec){if(vec.empty())return;cerr<<vec[0];for(auto it=vec.begin();++it!= vec.end();){cerr<<" "<<*it;}}
void debug(){cerr<<endl;}
template<class T> void debug(const T& t){dprint(t);cerr<<endl;}
template <class Head, class... Tail> void debug(const Head& head, const Tail&... tail){dprint(head);cerr<<" ";debug(tail...);}
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
ll updivide(ll a,ll b){if(a%b==0) return a/b;else return (a/b)+1;}

int n;
void dijkstra(vector<vector<pair<ll,ll>>>& graph,vector<long long> &distance,int start){
    priority_queue<pair<ll,ll>> PQ;
    vector<bool> checked(n,false);
    distance[start]=0;
    PQ.push(make_pair(0,start));
    int u;
    while(1){
        u=-1;
        while(!PQ.empty()){
            if(!checked[PQ.top().second]){
                u=PQ.top().second;
                distance[u]=-PQ.top().first;
                PQ.pop();
                break;
            }
            PQ.pop();
        }
        if(u==-1)break;
        checked[u]=true;
        for(int i=0;i<graph[u].size();i++){
            PQ.push(make_pair(-(distance[u]+graph[u][i].second),graph[u][i].first));
        }
    }
}

int main(){
    in(n);
    vector<vector<pair<ll,ll>>> graph(n);
    vector<ll> distance(n,1000000000000000000);
    int u,k,v,c,q;
    rep(i,n-1){
        in(u,v,c);
        graph[u-1].push_back(make_pair(v-1,c));
        graph[v-1].push_back(make_pair(u-1,c));
    }
    in(q,k);
    dijkstra(graph,distance,k-1);
    rep(i,q){
        in(u,v);
        out(distance[u-1]+distance[v-1]);
    }
}

Measured memory_bytes: 14004