#include<bits/stdc++.h>
using namespace std;
vector<vector<pair<int,int>>> g;
vector<int> in,out;
vector<int> tseen;
vector<int> depth;
vector<int> shop;
vector<long long> dist;
vector<vector<int>> p;
int t = 0;
void dfs(int rn) {
t++;
in[rn] = t;
tseen[rn] = 1;
for(auto [e,x] : g[rn]) {
if(tseen[e] == 1) continue;
p[e][0] = rn;
depth[e] = depth[rn]+1;
dist[e] = dist[rn] + x;
dfs(e);
}
out[rn] = t;
}
#define INF 2e15
vector<long long> best;
vector<vector<long long>> jmp;
long long bfs(int rn) {
long long wow = INF;
tseen[rn] = 1;
if(shop[rn] == 1) wow = dist[rn];
for(auto [a,b] : g[rn]) {
if(tseen[a] == 1) continue;
wow = min(wow, bfs(a));
}
best[rn] = wow;
jmp[rn][0] = wow - 2 * dist[rn];
for(int i = 1; i < 20; i++) {
p[rn][i] = p[p[rn][i-1]][i-1];
jmp[rn][i] = min(jmp[rn][i-1], jmp[p[rn][i-1]][i-1]);
}
return wow;
}
int main() {
int N,S,Q,E; cin >> N >> S >> Q >> E;
E--;
g.resize(N);
in = out = vector<int>(N,-1);
tseen = vector<int>(N,0);
depth = vector<int>(N,0);
shop = vector<int>(N,0);
p = vector<vector<int>>(N, vector<int>(20,E));
dist = vector<long long>(N,0);
vector<pair<int,int>> path;
best = vector<long long>(N,INF);
jmp = vector<vector<long long>>(N,vector<long long>(20,INF));
for(int i = 0; i < N-1; i++) {
int a,b,w; cin >> a >> b >> w;
a--;
b--;
g[a].push_back({b,w});
g[b].push_back({a,w});
path.push_back({a,b});
}
for(int i = 0; i < S; i++) {
int a; cin >> a;
a--;
shop[a] = 1;
}
t = 0;
dfs(E);
tseen = vector<int>(N,0);
bfs(E);
for(int q = 0; q < Q; q++) {
int I,R; cin >> I >> R;
I--; R--;
int gh = R;
int a,b;
a = path[I].first;
b = path[I].second;
if(dist[a] < dist[b]) swap(a,b);
if(!(in[a] <= in[R] and out[a] >= out[R])) {
cout << "escape" << "\n";
continue;
}
long long ans = INF;
for(int j = 19; j >= 0; j--) {
if(depth[R] - (1 << j) >= depth[a]) {
ans = min(ans, jmp[R][j]);
R = p[R][j];
}
}
ans = min(ans, jmp[a][0]); // include magic[a]
if(ans > 2e14) {
cout << "oo\n";
} else {
cout << ans + dist[gh] << "\n";
}
}
}
