#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 100000;
const ll inf = 1e18;
int n, s, q, e, t = 0;
vector<ll> in(N), out(N), magazin(N), x(N, inf), dp(N), d(N);
vector<pair<int, int>> much;
vector<vector<pair<int, int>>> vec(N);
vector<vector<ll>> lift(N, vector<ll>(18)), mn(N, vector<ll>(18));
void dfs(int u, int p)
{
in[u] = t ++;
lift[u][0] = p;
if(magazin[u])
x[u] = d[u];
for(auto [v, w] : vec[u])
if (v != p)
{
d[v] = d[u] + w;
dfs(v, u);
x[u] = min(x[u], x[v]);
}
dp[u] = (x[u] == inf ? inf : x[u] - 2 * d[u]);
mn[u][0] = dp[u];
out[u] = t ++;
}
bool is_ancestor(int u, int v)
{
return (in[u] <= in[v] && out[u] >= out[v]);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n >> s >> q >> e;
e --;
for(int i = 0; i < n - 1; i ++)
{
int u, v, w;
cin >> u >> v >> w;
u --;
v --;
much.emplace_back(u, v);
vec[u].emplace_back(v, w);
vec[v].emplace_back(u, w);
}
for(int i = 0; i < s; i ++)
{
int u;
cin >> u;
magazin[u - 1] = 1;
}
dfs(e, e);
for(int b = 1; b < 18; b ++)
for(int i = 0; i < n; i ++)
{
lift[i][b] = lift[lift[i][b - 1]][b - 1];
mn[i][b] = min(mn[i][b - 1], mn[lift[i][b - 1]][b - 1]);
}
while(q --)
{
int i, r;
cin >> i >> r;
i --;
r --;
auto [u, v] = much[i];
if(is_ancestor(u, v))
swap(u, v);
if(!is_ancestor(u, r))
cout << "escaped\n";
else
{
ll best = dp[u], dd = d[r];
for(int b = 17; b >= 0; b --)
if(is_ancestor(u, lift[r][b]))
{
best = min(best, mn[r][b]);
r = lift[r][b];
}
if(best == inf)
cout << "oo\n";
else
cout << dd + best << '\n';
}
}
}
