#include<bits/stdc++.h>
#define ii pair<int, int>
#define ll pair<long long, long long>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
using namespace std;
const int mod[2] = {1000000007, 998244353};
const int N = 1e5 + 1;
const long long inf = 1e16;
const string NAME = "landslide";
int n, s, q, h;
int pos[N];
vector<ii> adj[N];
struct edge{
int u, v, w;
edge(int _u = 0, int _v = 0, int _w = 0) : u(_u), v(_v), w(_w) {}
};
edge ed[N];
long long nearest[N], dist[N], jump[20][N];
int d[N], lg[N], in[N], out[N], cnt;
int p[20][N];
void DFS(int u){
in[u] = ++cnt;
for(auto [v, w] : adj[u]){
if(v == p[0][u])
continue;
p[0][v] = u;
d[v] = d[u] + 1;
dist[v] = dist[u] + w;
for(int i = 1; i <= lg[d[v]]; ++i)
p[i][v] = p[i - 1][p[i - 1][v]];
DFS(v);
}
out[u] = cnt;
}
void DFS_nearest(int u){
for(auto [v, w] : adj[u]){
if(v == p[0][u])
continue;
DFS_nearest(v);
nearest[u] = min(nearest[u], nearest[v]);
}
}
bool isAncestor(int u, int v){
return in[u] <= in[v] && in[v] <= out[u];
}
long long minPath(int u, int v){
long long res = inf;
int k = d[v] - d[u];
for(int i = lg[k]; i >= 0; --i)
if((k >> i) & 1)
res = min(res, jump[i][v]), v = p[i][v];
return min(res, nearest[u]);
}
void inp(){
cin >> n >> s >> q >> h;
for(int i = 1; i < n; ++i){
int u, v, w;
cin >> u >> v >> w;
ed[i] = edge(u, v, w);
adj[u].eb(v, w);
adj[v].eb(u, w);
}
for(int i = 1; i <= s; ++i)
cin >> pos[i];
}
void init(){
for(int i = 2; i <= n; ++i)
lg[i] = lg[i / 2] + 1;
for(int i = 1; i <= n; ++i)
nearest[i] = inf;
DFS(h);
for(int i = 1; i <= s; ++i)
nearest[pos[i]] = dist[pos[i]];
DFS_nearest(h);
for(int i = 1; i <= n; ++i){
if(nearest[i] < inf)
nearest[i] -= 2LL * dist[i];
jump[0][i] = nearest[i];
}
for(int l = 1; l <= lg[n]; ++l)
for(int i = 1; i <= n; ++i)
jump[l][i] = min(jump[l - 1][i], jump[l - 1][p[l - 1][i]]);
for(int i = 1; i < n; ++i){
auto [u, v, w] = ed[i];
if(in[u] > in[v])
swap(u, v);
ed[i] = edge(u, v, w);
}
}
void solve(){
init();
while(q--){
int id, u;
cin >> id >> u;
int v = ed[id].v;
if(!isAncestor(v, u))
cout << "escaped\n";
else{
long long res = minPath(v, u) + dist[u];
if(res >= inf)
cout << "oo\n";
else
cout << res << "\n";
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
if(fopen((NAME + ".inp").c_str(), "r")){
freopen((NAME + ".inp").c_str(), "r", stdin);
freopen((NAME + ".out").c_str(), "w", stdout);
}
inp();
solve();
}
