#include<bits/stdc++.h>
using namespace std;
#define NAME "FOX"
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FOD(i, a, b) for(int i = a; i >= b; i--)
#define int long long
#define ii pair<int, int>
#define fi first
#define se second
#define choanh1chuthivongduockhong ios_base::sync_with_stdio(false); \
cin.tie(NULL); \
cout.tie(NULL);
#define BIT(x, i) ((x >> i) & 1)
#define ALL(x) x.begin(), x.end()
const int maxn = 1e5 + 11;
const int LOGN = 20;
const int INF = 1e18;
int par[maxn][LOGN], mi[maxn][LOGN], dp[maxn], dis[maxn], tin[maxn], tout[maxn], ds[maxn], timedfs;
int n, s, q, h;
vector<ii> adj[maxn];
ii edge[maxn];
void dfs(int u, int p = -1) {
tin[u] = ++timedfs;
for(ii i : adj[u]) {
int v = i.se;
int w = i.fi;
if(v == p) continue;
ds[v] = ds[u] + 1;
dis[v] = dis[u] + w;
dfs(v, u);
dp[u] = min(dp[u], dp[v] + w);
par[v][0] = u;
}
if(dp[u] != INF) mi[u][0] = dp[u] - dis[u];
tout[u] = timedfs;
}
bool in(int u, int v) {
return (tin[u] <= tin[v] && tout[v] <= tout[u]);
}
int calc(int u, int len) {
int res = INF;
FOD(k, LOGN - 1, 0) {
if((1 << k) <= len) {
len -= (1 << k);
res = min(res, mi[u][k]);
u = par[u][k];
}
}
return res;
}
signed main() {
if(fopen(NAME".INP", "r")) {
freopen(NAME".INP", "r", stdin);
freopen(NAME".OUT", "w", stdout);
}
choanh1chuthivongduockhong;
cin >> n >> s >> q >> h;
FOR(i, 1, n - 1) {
int u, v, w; cin >> u >> v >> w;
adj[u].push_back({w, v});
adj[v].push_back({w, u});
edge[i] = {u, v};
}
FOR(i, 1, n) {
dp[i] = INF;
mi[i][0] = INF;
}
FOR(i, 1, s) {
int x; cin >> x;
dp[x] = 0;
}
dfs(h);
FOR(k, 1, LOGN - 1) {
FOR(i, 1, n) {
par[i][k] = par[par[i][k - 1]][k - 1];
mi[i][k] = min(mi[i][k - 1], mi[par[i][k - 1]][k - 1]);
}
}
while(q--) {
int i, r;
cin >> i >> r;
if(ds[edge[i].fi] > ds[edge[i].se]) swap(edge[i].fi, edge[i].se);
if(!in(edge[i].se, r)) {
cout << "escaped\n";
continue;
}
int res = dis[r] + calc(r, ds[r] - ds[edge[i].se] + 1);
if(res >= INF) {
cout << "oo\n";
} else {
cout << res << "\n";
}
}
return 0;
}
