#include <bits/stdc++.h>
#define ull uint64_t
#define ll long long int
#define pb push_back
#define mp make_pair
#define pi pair<int, int>
#define vi vector<int>
#define ff first
#define ss second
#define mx5 100005
#define mx52 200005
#define mx6 1000005
#define mod 1000000007
#define smod 998244353
#define nfs \
ios_base::sync_with_stdio(0); \
cin.tie(0); \
cout.tie(0);
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x)
{
cerr << '{';
__print(x.first);
cerr << ',';
__print(x.second);
cerr << '}';
}
template <typename T>
void __print(const T &x)
{
int f = 0;
cerr << '{';
for (auto &i : x)
cerr << (f++ ? "," : ""), __print(i);
cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v)
{
__print(t);
if (sizeof...(v))
cerr << ", ";
_print(v...);
}
#ifndef ONLINE_JUDGE
#define debug(x...) \
cerr << "[" << #x << "] = ["; \
_print(x)
#else
#define debug(x...)
#endif
template <typename T>
bool MinPlace(T &a, const T &b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
template <typename T>
bool MaxPlace(T &a, const T &b)
{
if (a < b)
{
a = b;
return true;
}
return false;
}
template <typename S, typename T>
ostream &operator<<(ostream &out, const pair<S, T> &p)
{
out << "{" << p.ff << ", " << p.ss << "}";
return out;
}
template <typename T>
ostream &operator<<(ostream &out, const vector<T> &v)
{
out << "[";
for (int i = 0; i < (int)v.size(); i++)
{
out << v[i];
if (i != (int)v.size() - 1)
out << ", ";
}
out << "]";
return out;
}
int main()
{
nfs;
const int H = 17;
const uint64_t inf = 1e14 + 1;
int n, s, q, root;
cin >> n >> s >> q >> root;
vector<array<int, 3>> edges(n);
vector<vector<pi>> gr(n + 1);
vi in(n + 1, 0), out(n + 1, 0), depth(n + 1, 0);
vector<uint64_t> closest(n + 1, inf);
vector<vi> up(n + 1, vi(H, 0));
vector<vector<uint64_t>> upEdgeCost(n + 1, vector<uint64_t>(H, 0));
vector<vector<uint64_t>> upAns(n + 1, vector<uint64_t>(H, inf));
for (int i = 1; i < n; i++)
{
cin >> edges[i][0] >> edges[i][1] >> edges[i][2];
gr[edges[i][0]].pb({edges[i][1], edges[i][2]});
gr[edges[i][1]].pb({edges[i][0], edges[i][2]});
}
for (int i = 0; i < s; i++)
{
int u;
cin >> u;
closest[u] = 0;
}
int timer = 1;
function<void(int, int, int)> dfs = [&](int u, int p, int d)
{
in[u] = ++timer;
depth[u] = d + 1;
for (auto [v, w] : gr[u])
{
if (v == p)
continue;
dfs(v, u, d + 1);
MinPlace(closest[u], closest[v] + w);
}
out[u] = ++timer;
};
dfs(root, 0, 0);
out[0] = ++timer;
function<bool(int, int)> is_anc = [&](int u, int v)
{
return in[u] <= in[v] && out[v] <= out[u];
};
function<void(int, int, uint64_t)> dfs2 = [&](int u, int p, uint64_t w)
{
up[u][0] = p;
upEdgeCost[u][0] = w;
for (int i = 1; i < H; i++)
{
up[u][i] = up[up[u][i - 1]][i - 1];
upEdgeCost[u][i] = upEdgeCost[u][i - 1] + upEdgeCost[up[u][i - 1]][i - 1];
}
upAns[u][0] = min(closest[u], w + closest[p]);
debug(u, p, w, closest[u], closest[p], upAns[u][0]);
for (int i = 1; i < H; i++)
upAns[u][i] = min(upAns[u][i - 1], upEdgeCost[u][i - 1] + upAns[up[u][i - 1]][i - 1]);
debug(upAns[u]);
for (auto [v, wc] : gr[u])
if (v != p)
dfs2(v, u, wc);
};
dfs2(root, 0, inf);
debug(in, out, depth, up);
debug(closest);
debug(upAns);
debug(upEdgeCost);
while (q--)
{
int eno, u;
cin >> eno >> u;
auto [a, b, w] = edges[eno];
if (depth[a] > depth[b])
swap(a, b);
if (!is_anc(b, u))
{
cout << "escaped\n";
continue;
}
uint64_t ans = inf, edgeCost = 0;
for (int i = H - 1; i >= 0; i--)
{
if (depth[up[u][i]] > depth[b])
{
MinPlace(ans, edgeCost + upAns[u][i]);
edgeCost += upEdgeCost[u][i];
u = up[u][i];
}
}
if (u != b)
{
MinPlace(ans, edgeCost + upAns[u][0]);
edgeCost += upEdgeCost[u][0];
u = up[u][0];
}
if (ans == inf)
cout << "oo\n";
else
cout << ans << "\n";
}
}
