#include <bits/stdc++.h>
#define PB push_back
#define ST first
#define ND second
#define _ ios_base::sync_with_stdio(0); cin.tie(0);
//mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
using namespace std;
using ll = long long;
using pi = pair<int,int>;
using vi = vector<int>;
struct Query {
int id, block;
};
struct Edge {
int v, cost, id;
};
struct Node {
ll f, g;
};
const int nax = 100 * 1000 + 10;
const ll INF = (ll)1e16+10;
int n,q,s,root,nr;
int in[nax], out[nax];
int edge_block[nax];
ll dist[nax];
bool is_shop[nax];
vector<Query>qr[nax];
vector<Edge>V[nax];
Node T[(1<<18)];
ll ans[nax];
void propagate(int x) {
T[2*x].g += T[x].g;
T[2*x+1].g += T[x].g;
T[x].g = 0;
}
void update(int a,int b, ll x, int l, int r, int v) {
//~ cout << a << " " << b << ": "<<l << " " << r << "\n";
if(a <= l && r <= b) {
T[v].g += x;
return;
}
propagate(v);
int mid = (l+r)/2;
if(a <= mid) update(a,b,x,l,mid,v*2);
if(mid < b) update(a,b,x,mid+1,r,v*2+1);
T[v].f = min(T[2*v].f + T[2*v].g, T[2*v+1].f + T[2*v+1].g);
}
ll query(int a,int b,int l, int r, int v) {
//~ cout << l << " " << r << "\n";
if(a <= l && r <= b) {
return T[v].f + T[v].g;
}
propagate(v);
int mid = (l+r)/2;
ll w = INF;
if(a <= mid) w = min(w, query(a,b,l,mid,v*2));
if(mid < b) w = min(w, query(a,b,mid+1,r,v*2+1));
return w + T[v].g;
}
void dfs(int x, int p) {
in[x] = nr++;
for(auto nbh : V[x]) {
if(nbh.v != p) {
edge_block[nbh.id] = nbh.v;
dist[nbh.v] = dist[x] + nbh.cost;
dfs(nbh.v, x);
}
}
out[x] = nr;
}
void dfsAns(int x,int p) {
for(auto qre : qr[x]) {
int v = edge_block[qre.block];
if(in[v] <= in[x] && in[x] <= out[v] - 1) {
//~ cout << "X\n";
ll d = query(in[v], out[v] - 1, 0, n-1, 1);
//~ cout << "D : "<<d << "\n";
ans[qre.id] = d;
} else {
ans[qre.id] = -1;
}
}
//~ cout << x << "\n";
for(auto nbh : V[x]) {
if(nbh.v != p) {
//~ cout << in[nbh.v] << " " << out[nbh.v] << "\n";
update(in[nbh.v], out[nbh.v] - 1, -2 * nbh.cost, 0, n-1, 1);
update(0, n-1, nbh.cost, 0, n-1, 1);
dfsAns(nbh.v, x);
update(in[nbh.v], out[nbh.v] - 1, 2 * nbh.cost, 0, n-1, 1);
update(0, n-1, -nbh.cost, 0, n-1, 1);
}
}
}
void init(int l, int r, int v) {
T[v].f = INF;
if(l == r) {
return;
}
init(l, (l+r)/2, v*2);
init((l+r)/2 + 1, r, v*2+1);
}
int main() {_
cin >> n >> s >> q >> root;
for(int a,b,w,i=1; i < n; ++i) {
cin >> a >> b >> w;
V[a].PB({b,w,i});
V[b].PB({a,w,i});
}
for(int a,i = 1; i <= s; ++i) {
cin >> a;
is_shop[a] = 1;
}
for(int a,b,i=1; i<= q; ++i) {
cin >> a >> b;
qr[b].PB({i,a});
}
dfs(root, 0);
//~ init(0, n-1, 1);
for(int i = 1; i <= n; ++i) {
//~ cout << "I : " << in[i] << " " << out[i] << "\n";
if(is_shop[i]) {
update(in[i], in[i], dist[i], 0, n-1, 1);
} else {
update(in[i], in[i], INF, 0, n-1, 1);
}
}
dfsAns(root, 0);
for(int i = 1; i <= q; ++i) {
if(ans[i] == -1) {
cout << "escaped\n";
} else if(ans[i] > (ll)1e14) {
cout << "oo\n";
} else {
cout << ans[i] << "\n";
}
}
}
