#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pii pair <int , int>
#define arr3 array <int , 3>
using namespace std;
const int INF = 1e18;
const int maxn = 2e5 + 7;
bool mark[maxn];
int tin[maxn] , tout[maxn] , time_dfs = 0;
int N , Q , S , E , cnt[maxn] , dp[maxn] , jump[20][maxn] , mn[20][maxn] , dep[maxn];
vector <pii> g[maxn];
arr3 edge[maxn];
void dfs(int u , int p)
{
tin[u] = ++time_dfs;
dp[u] = INF;
if(mark[u]) dp[u] = dep[u];
for(pii e: g[u])
{
int v = e.fi;
int w = e.se;
if(v == p) continue;
jump[0][v] = u;
dep[v] = dep[u] + w;
dfs(v , u);
dp[u] = min(dp[v], dp[u]);
mn[0][v] = dp[u] - 2*dep[u];
}
tout[u] = ++time_dfs;
}
void solve()
{
cin >> N >> S >> Q >> E;
for(int i = 1; i < N; i++)
{
cin >> edge[i][0] >> edge[i][1] >> edge[i][2];
int u = edge[i][0] , v = edge[i][1] , w = edge[i][2];
g[u].push_back({v , w});
g[v].push_back({u , w});
}
for(int i = 1; i <= S; i++)
{
int u; cin >> u; mark[u] = 1;
}
dfs(E , E);
dep[0] = -1;
for(int j = 1; j < 19; j++)
{
for(int i = 1; i <= N; i++)
{
jump[j][i] = jump[j-1][jump[j-1][i]];
}
}
while(Q--)
{
int I , R; cin >> I >> R;
int u = edge[I][0] , v = edge[I][1];
if(dep[u] < dep[v]) swap(u , v);
if(tin[u] <= tin[R] && tout[R] <= tout[u])
{
int ans = dp[R] - dep[R];
int h = dep[R];
for(int i = 18; i >= 0; i--)
{
if(dep[jump[i][R]] >= dep[u])
{
ans = min(ans , h + mn[i][R]);
R = jump[i][R];
}
}
ans = min(ans , dp[R] - 2*dep[R] + h);
if(ans > 1e16) cout << "oo" << '\n';
else cout << ans << '\n';
}
else cout << "escaped" << '\n';
}
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
//freopen("inp.txt", "r" , stdin);
//freopen("out.txt", "w" , stdout);
solve();
return 0;
}
