#pragma GCC optimize ("O3,unroll-loops,Ofast")
//#pragma GCC target ("avx2,bmi,bmi2,popcnt")
#include <bits/stdc++.h>
#define F first
#define pb push_back
#define sz size()
#define S second
using namespace std;
typedef long long int ll;
const int N = 1e5 + 10, LG = 20;
const ll INF = 1e18;
int n,s,q,e,lg2[N],st[N],ft[N],timer = 0;
ll dp[N],h[N],hi[N],val[N],mini[N][LG],up[N][LG];
vector<pair<int,int>> adj[N],edg;
vector<ll> vec;
bool shop[N];
void dfs(int v,int p){
st[v] = ++timer;
up[v][0] = p;
for(int j=1;j<LG;j++)
up[v][j] = up[up[v][j-1]][j-1];
if(shop[v])
dp[v] = 0;
for(auto x:adj[v]){
int u = x.F, w = x.S;
if(u == p)
continue;
h[u] = h[v] + w;
hi[u] = hi[v] + 1;
dfs(u,v);
dp[v] = min(dp[v], dp[u] + w);
}
ft[v] = ++timer;
}
void dfs2(int v,int p){
mini[v][0] = min(val[v], val[p]);
for(int j=1;j<LG;j++)
mini[v][j] = min(mini[v][j-1], mini[up[v][j-1]][j-1]);
for(auto x:adj[v]){
int u = x.F;
if(u == p)
continue;
dfs2(u,v);
}
}
bool is_anc(int anc,int v){
return (st[anc] <= st[v] && ft[anc] >= ft[v]);
}
ll minx(int v,int x){
ll ans = val[v];
for(int j=LG-1;j>-1;j--){
if(x >= (1 << j)){
ans = min(ans, mini[v][j]);
v = up[v][j];
x -= (1 << j);
}
}
return ans;
}
inline void init(){
for(int i=0;i<N;i++){
dp[i] = INF;
}
lg2[1] = 0;
for(int i=2;i<N;i++)
lg2[i] = lg2[i/2] + 1;
}
inline void input(){
cin >> n >> s >> q >> e;
e--;
int x,y,w;
for(int i=0;i<n-1;i++){
cin >> x >> y >> w;
x--, y--;
adj[x].pb({y,w}), adj[y].pb({x,w});
edg.pb({x,y});
}
for(int i=0;i<s;i++){
cin >> x;
shop[--x] = 1;
}
}
inline void solve(){
int x,y;
hi[e] = 0, h[e] = 0;
dfs(e,e);
for(int i=0;i<n;i++){
val[i] = dp[i] - h[i];
// cout << dp[i] << ' ' << h[i] << ' ' << i << endl;
}
dfs2(e,e);
/* for(int i=0;i<n;i++){
for(int j=0;j<LG;j++){
if(mini[i][j] > 1e17)
cout << "INF ";
else
cout << mini[i][j] << ' ';
}
cout << endl;
}*/
while(q--){
cin >> x >> y; // edge , vertex
x--, y--;
int v = edg[x].F, u = edg[x].S;
if(h[v] < h[u])
swap(v,u);
if(!is_anc(v,y)){
cout << "escaped" << endl;
}
else{
ll ans = minx(y,hi[y]-hi[v]);
// cout << ans << ' ';
ans += h[y];
if(ans > 1e16)
cout << "oo" << endl;
else
cout << ans << endl;
}
}
}
int main(){
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
init();
int queries = 1;
// cin >> queries;
while(queries--){
input();
solve();
}
return 0;
}
