#include<bits/stdc++.h>
#define int long long
#define ii pair<int,int>
#define fi first
#define se second
using namespace std;
const int N = 1e5 + 5, oo = 1e18;
int n, s, q, e, f[N], dist[N];
int up[N][25], mi[N][25], h[N];
int tin[N], tout[N], timeDfs;
vector<ii> g[N];
struct EDGE
{
int u, v, c;
} edge[N];
void dfs(int u, int par)
{
tin[u] = ++timeDfs;
for(auto &[v, c] : g[u])
{
if(v == par) continue;
dist[v] = dist[u] + c;
up[v][0] = u;
for(int j = 1; j <=18; j++)
up[v][j] = up[up[v][j - 1]][j - 1];
h[v] = h[u] + 1;
dfs(v, u);
if(f[v] != oo)
f[u] = min(f[u], f[v] + c);
mi[v][0] = min(f[v] - dist[v], f[u] - dist[u]);
}
tout[u] = timeDfs;
}
void init()
{
for(int j = 1; j <= 18; j++)
{
for(int i = 1; i <= n; i++)
{
mi[i][j] = min(mi[i][j], mi[up[i][j - 1]][j - 1]);
}
}
}
main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> s >> q >> e;
for(int i = 1; i < n; i++)
{
int u, v, c; cin >> u >> v >> c;
edge[i] = {u, v, c};
g[u].push_back({v, c});
g[v].push_back({u, c});
}
for(int i = 1; i <= n; i++)
f[i] = oo;
for(int i = 1; i <= s; i++)
{
int u; cin >> u;
f[u] = 0;
}
for(int j = 0; j <= 18; j++)
up[e][j] = e;
h[e] = 1;
dfs(e, -1);
init();
while(q--)
{
int i, r; cin >> i >> r;
int u = edge[i].u;
int v = edge[i].v;
if(dist[v] > dist[u]) swap(u, v);
if(tin[u] <= tin[r] && tout[u] >= tin[r])
{
int tmp_r = r;
int ans = oo;
for(int j = 18; j >= 0; j--)
{
if(h[up[tmp_r][j]] >= h[u])
{
ans = min(ans, dist[r] + mi[tmp_r][j]);
tmp_r = up[tmp_r][j];
}
}
if(ans == oo) cout << "oo" << '\n';
else cout << ans << '\n';
}
else
{
cout << "escaped\n";
}
}
}
