#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define fr first
#define sc second
#define clr(a, x) memset(a, x, sizeof(a))
#define dbg(x) cout<<"("<<#x<<"): "<<x<<endl;
#define printvector(arr) for (auto it = arr.begin(); it != arr.end(); ++it) cout<<*it<<" "; cout<<endl;
#define all(v) v.begin(), v.end()
#define lcm(a, b) (a * b)/__gcd(a, b)
#define int long long int
#define printvecpairs(vec) for(auto it: vec) cout<<it.fr<<' '<<it.sc<<endl;
#define endl '\n'
#define float long double
const int MOD = 1e9 + 7;
const int INF = 2e15;
const int MAXN = 1e5 + 5;
vector<pair<int, int>> adj[MAXN];
int up[MAXN][100], upmn[MAXN][100], depth[MAXN], dist[MAXN];
vector<pair<int, int>> edges;
bool flag[MAXN];
int timer = 0, n, l;
int tout[MAXN], tin[MAXN];
int dp[MAXN];
void dfs(int v, int p, int d, int dpth){
timer++;
dist[v] = d;
depth[v] = dpth;
tin[v] = timer;
up[v][0] = p;
for(int i=1;i<=l;i++){
up[v][i] = up[up[v][i-1]][i-1];
}
for(auto &[u, w]: adj[v]){
if(u != p){
dfs(u, v, d+w, dpth+1);
}
}
timer++;
tout[v] = timer;
}
bool isanc(int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
void preprocess(){
timer = 0;
clr(tout, 0);
clr(tin, 0);
l = 20;
clr(flag, 0);
clr(depth, 0);
clr(up, 0);
clr(dist, 0);
}
int lca(int u, int v){
if(isanc(u, v)) return u;
if(isanc(v, u)) return v;
for(int i = l;i >= 0;i--){
if(!isanc(up[u][i], v))
u = up[u][i];
}
return up[u][0];
}
int dfs0(int u, int p){
int ans = INF;
if(flag[u]) ans = dist[u];
for(auto &[v, w]: adj[u]){
if(v == p) continue;
ans = min(ans, dfs0(v, u));
}
dp[u] = -2* dist[u] + ans;
return ans;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
int n, c, q, s;
cin>>n>>c>>q>>s;
preprocess();
for(int i=0;i<n-1;i++){
int u, v, w;
cin>>u>>v>>w;
adj[u].pb({v, w});
adj[v].pb({u, w});
edges.pb({u, v});
}
for(int i=0;i<c;i++){
int x; cin>>x;
flag[x] = true;
}
dfs(s, s, 0, 0);
dfs0(s, -1);
for(int i=1;i<=n;i++){
upmn[i][0] = dp[up[i][0]];
}
for(int i=1;i<=l;i++){
for(int j = 1;j<=n;j++){
upmn[j][i]= min(upmn[j][i-1], upmn[up[j][i-1]][i-1]);
}
}
while(q--){
int i, u;
cin>>i>>u;
i--;
int root = -1;
if(depth[edges[i].fr] < depth[edges[i].sc]){
root = edges[i].sc;
} else {
root = edges[i].fr;
}
if(!isanc(root, u)){
cout<<"escaped"<<endl;
continue;
}
int curr = u;
int ans = dp[u];
for(int i = l;i >= 0;i--){
if(depth[up[curr][i]] >= depth[root]){
ans = min(ans, upmn[curr][i]);
curr = up[curr][i];
}
}
if(ans+dist[u] >= 1e14){
cout<<"oo"<<endl;
} else {
cout<<ans+dist[u]<<endl;
}
}
return 0;
}
