#include <bits/stdc++.h>
#define task "1"
#define ll long long
#define double long double
#define ii pair<int, int>
#define li pair<ll, int>
#define fi first
#define se second
#define all(v) (v).begin(), (v).end()
#define FULL(i) ((1LL << i) - 1)
#define MASK(i) (1LL << i)
#define c_bit(i) __builtin_popcountll(i)
#define Bit(mask, i) ((mask >> i) & 1)
#define onbit(mask, i) ((mask) bitor (1LL << i))
#define offbit(mask, i) ((mask) &~ (1LL << i))
using namespace std;
const int maxn = 1e5 + 5;
const ll oo = 1e18;
const int mod = 1e9 + 7;
const int dx[] = {0, 1, 0, -1} , dy[] = {1, 0, -1, 0};
template <class X, class Y> bool maximize(X &a, const Y &b)
{
if(a < b) return a = b, true;
return false;
}
template <class X, class Y> bool minimize(X &a, const Y &b)
{
if(a > b) return a = b, true;
return false;
}
int n, s, q, h, head[maxn], pos[maxn], par[maxn], sz[maxn], in[maxn], out[maxn], depth[maxn];
vector<ii> adj[maxn]; bool mark[maxn]; ll d[maxn], dp[maxn], mi[maxn][20];
struct Edge{
int u, v, w;
} edges[maxn];
void dfs(int u, int p)
{
static int timeDfs = 0;
in[u] = ++ timeDfs;
dp[u] = mark[u] ? 0 : oo;
sz[u] = 1;
int iMax = -1;
for(int i = 0; i < adj[u].size(); ++ i){
auto [v, w] = adj[u][i];
if(v == p) continue;
par[v] = u;
d[v] = d[u] + w;
depth[v] = depth[u] + 1;
dfs(v, u);
minimize(dp[u], dp[v] + w);
sz[u] += sz[v];
if(!~iMax || sz[adj[u][iMax].fi] < sz[v]) iMax = i;
}
out[u] = timeDfs;
if(~iMax) swap(adj[u][0], adj[u][iMax]);
}
void hld(int u)
{
static int id = 0;
pos[u] = ++ id;
for(auto [v, _] : adj[u]) if(par[v] == u){
if(sz[v] << 1 >= sz[u]) head[v] = head[u];
else head[v] = v;
hld(v);
}
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(nullptr);
if(fopen(task".inp", "r")){
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin >> n >> s >> q >> h;
for(int i = 1; i < n; ++ i){
int u, v, w; cin >> u >> v >> w;
edges[i] = {u, v, w};
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
for(int i = 1; i <= s; ++ i){
int u; cin >> u;
mark[u] = true;
}
dfs(h, 0);
hld(h);
auto inSubTree = [&](int v, int u){
return in[u] <= in[v] && in[v] <= out[u];
};
for(int u = 1; u <= n; ++ u) mi[pos[u]][0] = dp[u] - d[u];
for(int k = 1; 1 << k <= n; ++ k) for(int i = 1; i + (1 << k) <= n; ++ i)
mi[i][k] = min(mi[i][k - 1], mi[i + (1 << k - 1)][k - 1]);
auto get = [&](int l, int r){
int h = __lg(r - l + 1);
return min(mi[l][h], mi[r - (1 << h) + 1][h]);
};
while(q --){
int e, x; cin >> e >> x;
auto [u, v, _] = edges[e];
if(depth[u] < depth[v]) swap(u, v);
if(!inSubTree(x, u)) { cout << "escaped\n"; continue; }
ll res = oo;
int d_x = d[x];
while(head[x] != head[u]){
minimize(res, get(pos[head[x]], pos[x]) + d_x);
x = par[head[x]];
}
minimize(res, get(pos[u], pos[x]) + d_x);
if(res == oo) cout << "oo\n";
else cout << res << '\n';
}
return 0;
}
