#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MAXN = 2e5 + 5;
int N, S, Q, E;
vector <pair <int, int>> adj[MAXN];
bool isspec[MAXN];
int h[MAXN];
long long sum[MAXN];
int par[MAXN], tin[MAXN], tout[MAXN], timeDFS;
long long f[MAXN];
int P[MAXN][20];
void dfs(int u, int p = - 1){
f[u] = 2e18;
if(isspec[u]) f[u] = sum[u];
tin[u] = ++ timeDFS;
for(pair <int, int> &it : adj[u]) if(it.first != p){
int v = it.first, w = it.second;
par[v] = u;
h[v] = h[u] + 1;
P[v][0] = u;
for(int j = 1; (1 << j) <= N; j++){
P[v][j] = P[P[v][j - 1]][j - 1];
}
sum[v] = sum[u] + w;
dfs(v, u);
f[u] = min(f[u], f[v]);
}
tout[u] = ++ timeDFS;
}
/// h[v] - 2 * sum LCA[u, v]
int sz[MAXN], heavy[MAXN], arr[MAXN];
void dfs_sz(int u){
sz[u] = 1;
for(auto it : adj[u]) if(it.first != par[u]){
int v = it.first;
dfs_sz(v);
sz[u]+= sz[v];
if(sz[v] > sz[heavy[u]]) heavy[u] = v;
}
}
int head[MAXN], cur[MAXN], pos[MAXN], timedfs = 0, crt = 0;
void dfs_hld(int u){
if(head[crt] == 0) head[crt] = u;
pos[u] = ++ timedfs;
cur[u] = crt;
arr[pos[u]] = u;
if(heavy[u]) dfs_hld(heavy[u]);
for(auto it : adj[u]) if(it.first != par[u] && it.first != heavy[u]){
crt++;
dfs_hld(it.first);
}
}
long long st[4 * MAXN];
void build(int id, int l, int r){
if(l == r){
int u = arr[l];
st[id] = f[u] - 2 * sum[u];
return;
}
int mid = (l + r) >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
st[id] = min(st[id << 1], st[id << 1 | 1]);
}
long long get(int id, int l, int r, int u, int v){
if(l > v || r < u) return 2e18;
if(l >= u && r <= v) return st[id];
int mid = (l + r) >> 1;
return min(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}
long long get(int u, int p){
long long res = 2e18;
long long cur_sum = sum[u];
while(cur[u] != cur[p]){
res = min(res, get(1, 1, N, pos[head[cur[u]]], pos[u]));
u = par[head[cur[u]]];
}
res = min(res, get(1, 1, N, pos[p], pos[u]));
if(res >= 1e18) return 1e18;
return cur_sum + res;
}
bool isParent(int u, int v){
return tin[u] <= tin[v] && tout[u] >= tout[v];
}
int LCA(int u, int v){
if(h[u] < h[v]) swap(u, v);
int z = __lg(h[u]);
for(int s = z; s >= 0; s--) if(h[u] - h[v] >= (1 << s)) u = P[u][s];
if(u == v) return u;
for(int s = z; s >= 0; s--) if(P[u][s] != P[v][s]) u = P[u][s], v = P[v][s];
return P[u][0];
}
int dist(int u, int v){
return h[u] + h[v] - 2 * h[LCA(u, v)];
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> N >> S >> Q >> E;
vector <array <int, 2>> edges(N + 5, {0, 0});
for(int i = 1; i <= N - 1; i++){
int u, v, w; cin >> u >> v >> w;
adj[u].push_back(make_pair(v, w));
adj[v].push_back(make_pair(u, w));
edges[i] = {u, v};
}
for(int i = 1; i <= S; i++){
int u; cin >> u;
isspec[u] = true;
}
dfs(E);
dfs_sz(E);
dfs_hld(E);
for(int i = 1; i <= 4 * N; i++){
st[i] = 2e18;
}
build(1, 1, N);
while(Q--){
int id_road, id_node;
cin >> id_road >> id_node;
int u = edges[id_road][0], v = edges[id_road][1];
if(h[u] > h[v]) swap(u, v);
if(dist(E, u) + dist(u, v) + dist(v, id_node) == dist(E, id_node)){
long long res = get(id_node, v);
if(f[id_node] < 1e18)
res = min(res, f[id_node] - sum[id_node]);
if(res >= 1e18) cout << "oo\n";
else cout << res << "\n";
} else{
cout << "escaped" << '\n';
}
}
return 0;
}
