#include <iostream>
#include <vector>
#define fi first
#define se second
using namespace std;
const long long maxw = 1e18;
const int maxn = 1e5 + 5;
int n, s, q, e;
int in[maxn], out[maxn];
vector <pair <int, int>> adj[maxn];
int cnt;
long long d[maxn];
int deg[maxn];
long long f[maxn][18], g[maxn];
bool dd[maxn];
int p1[maxn][18];
struct TEdge {
int u, v, w;
};
TEdge edg[maxn];
void DFS(int u, int p) {
in[u] = ++cnt;
if(dd[u]) g[u] = 0;
for(pair <int, int> i : adj[u]) {
if(i.fi == p) continue;
int v = i.fi;
int w = i.se;
d[v] = d[u] + w;
deg[v] = deg[u] + 1;
p1[v][0] = u;
for(int j = 1; (1 << j) <= deg[v]; ++j) p1[v][j] = p1[p1[v][j - 1]][j - 1];
DFS(i.fi, u);
g[u] = min(g[u], g[v] + w);
}
// f[u][0] = g[u] - d[u];
// for(int j = 1; (1 << j) <= deg[u] + 1; ++j) f[u][j] = min(f[u][j - 1], f[p1[u][j - 1]][j - 1]);
out[u] = ++cnt;
}
void DFS1(int u, int p) {
for(auto i : adj[u]) {
if(i.fi == p) continue;
int v = i.fi;
int w = i.se;
if(g[v] == 1e18) f[v][0] = 1e18;
else f[v][0] = g[v] - d[v];
for(int j = 1; (1 << j) <= deg[v] + 1; ++j) f[v][j] = min(f[v][j - 1], f[p1[v][j - 1]][j - 1]);
DFS1(v, u);
}
}
long long solve(int u, int v) {
int tmp = deg[v] - deg[u] + 1;
long long res = 1e18;
int tmp1 = 0;
while(tmp) {
if(tmp % 2) {
res = min(res, f[v][tmp1]);
v = p1[v][tmp1];
}
++tmp1;
tmp /= 2;
}
return res;
}
int main()
{
ios_base::sync_with_stdio(NULL); cin.tie(nullptr);
cin >> n >> s >> q >> e;
for(int i = 1; i < n; ++i) {
cin >> edg[i].u >> edg[i].v >> edg[i].w;
adj[edg[i].u].push_back({edg[i].v, edg[i].w});
adj[edg[i].v].push_back({edg[i].u, edg[i].w});
}
for(int i = 1; i <= s; ++i) {
int u;
cin >> u;
dd[u] = 1;
}
fill(g + 1, g + n + 1, 1e18);
DFS(e, 0);
DFS1(e, 0);
while(q--) {
int id, c;
cin >> id >> c;
int u = edg[id].u;
int v = edg[id].v;
if(p1[v][0] == u) swap(u, v);
if(in[u] > in[c] || out[u] < out[c]) {
cout << "escaped" << '\n';
continue;
}
long long ans = solve(u, c);
if(ans == 1e18) cout << "oo" << '\n';
else cout << ans + d[c] << '\n';
}
return 0;
}
