#include <bits/stdc++.h>
using namespace std;
#define int long long
#define vo vector
#define pb push_back
#define se second
#define fi first
#define all(v) v.begin(), v.end()
typedef vector<int> vi;
typedef pair<int, int> pii;
#define rep(i, a, b) for(int i=(a); i<b; i++)
#define pr1(x) cerr << #x << '=' << x << ' ';
//for google contests
#define umap unordered_map
#define uset unordered_set
#define repd(i, a, b) for(int i=(b-1); i >= a; i--)
void _pr(signed x) {cerr << x;}
void _pr(long long x) {cerr << x;}
void _pr(size_t x) {cerr << x;}
void _pr(double x) {cerr << x;}
void _pr(char x) {cerr << '\'' << x << '\'';}
void _pr(const char* x) {cerr << x;}
void _pr(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V> void _pr(const pair<T, V> &x);
template<typename T, typename V> void _pr(const pair<T, V> &x) {cerr << "\e[95m" << "[ "; _pr(x.first); cerr << ", "; _pr(x.second); cerr << "\e[95m" << ']';}
template<typename T> void _pr(const T &x) {int F=0; cerr << '{'; for(auto &i: x) cerr << (F++ ? ", " : ""), _pr(i); cerr << "\e[91m" << '}';}
template <typename T, typename... V> void _pr(T t, V... v) {_pr(t); if(sizeof...(v)) cerr << ", "; _pr(v...);}
#define pr(x...) cerr << "\e[91m" << __func__ << ':' << __LINE__ << " [" << #x << "] = ["; _pr(x); cerr << "\e[91m" << ']' << "\033[0m" << endl;
//go for outline with ;, then details
int const inf = 1e15, mxn = 1e5+4, mxlog=20;
int n, q, s, e, tin[mxn], tout[mxn], dep[mxn], timer, up[mxn][mxlog], shops[mxn];
int dist[mxn]; //from root
vi dp; //stores (distance to closest shop in subtree) + (distance to root, aka e)
int liftdp[mxn][mxlog];
vo<vo<array<int, 3>>> adj;
int dfs(int at, int p, int depth, int d){ // return distance to closest shop
tin[at] = timer++; dep[at] = depth; dist[at] = d;
up[at][0] = p;
rep(k, 1, mxlog){
up[at][k] = up[up[at][k-1]][k-1];
}
int ret = inf;
for(auto [x, w, edgeind]: adj[at]){
if(x!=p){
ret = min(ret, w+dfs(x, at, depth+1, d+w));
}
}
tout[at]=timer;
if(shops[at]) ret = 0;
if(ret==inf) dp[at] = inf;
else dp[at] = ret - dist[at];
return ret;
}
void dfsDP(int at, int p){
liftdp[at][0] = dp[p];
rep(k, 1, mxlog){
liftdp[at][k] = min(liftdp[at][k-1], liftdp[up[at][k-1]][k-1]);
}
for(auto [x, w, edgeind]: adj[at]){
if(x!=p) dfsDP(x, at);
}
}
bool is_ancestor(int u, int v){
return tin[u]<=tin[v]&&tout[u]>=tout[v];
}
int binary_lift(int v, int d){
int ret = dp[v];
rep(i, 0, mxlog){
if((d>>i) & 1){
ret = min(ret, liftdp[v][i]);
v = up[v][i];
}
}
return ret;
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
cin>>n>>s>>q>>e; e--;
adj.resize(n); vo<pii> edgetonode(n); dp.resize(n);
rep(i, 0, n-1){
int a, b, w; cin>>a>>b>>w; a--, --b;
adj[a].pb({b, w, i}), adj[b].pb({a, w, i});
edgetonode[i] = {a, b};
}
rep(i, 0, s){
int c; cin>>c; c--;
shops[c] = 1;
}
// preprocess
dfs(e, e, 0, 0);
dfsDP(e, e);
// process queries
rep(_, 0, q){
int edge, v; cin>>edge>>v; edge--, v--;
// check if escapable: push blocked edge to deeper node and check if it is ancestor to village r
auto [a, b] = edgetonode[edge]; if(dep[a] > dep[b]) swap(a, b);
if(is_ancestor(b, v)){
int ret = binary_lift(v, dep[v]-dep[b]);
if(ret==inf) cout << "oo\n";
else cout << ret + dist[v] << "\n";
}
else{
cout << "escaped\n";
}
}
}
