#include<bits/stdc++.h>
using namespace std;
// define
#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
#define ll long long
#define ii pair <int , int>
#define iii pair <int , ii>
#define se second
#define fi first
#define all(v) (v).begin() , (v).end()
#define Unique(v) sort(all(v)) , v.resize(unique(all(v)) - v.begin())
#define bit(x,i) (((x) >> (i)) & 1LL)
#define flip(x,i) ((x) ^ (1LL << (i)))
#define ms(d,x) memset(d , x , sizeof(d))
#define exist __exist
#define ends __ends
#define visit visited
#define left __left
#define right __right
#define prev __prev
#define next __next
#define sitingfake 1
#define orz 1
//constant
const long long mod = 1e9 + 7;
const long long linf = 4557430888798830399LL;
const long long nlinf = -4485090715960753727LL;
const int inf = 1061109567;
const int ninf = -1044266559;
const int dx[] = {0 , -1 , 0 , 1};
const int dy[] = {-1 , 0 , 1 , 0};
template<typename T> bool maximize(T &a, const T &b)
{
if(a < b) {a = b; return 1;}
return 0;
}
template<typename T> bool minimize(T &a, const T &b)
{
if(a > b) {a = b; return 1;}
return 0;
}
void Plus(ll & a ,ll b)
{
b %= mod;
a += b;
if(a < 0) a += mod;
a %= mod;
return;
}
void Mul(ll & a, ll b)
{
(a *= (b % mod)) %= mod;
return;
}
//code
const int maxn = 1e5 + 7;
int n , q;
vector <ii> adj[maxn];
int root , numshops;
int depth[maxn] , in[maxn] , out[maxn] , par[maxn][20] , timer;
ll mi[maxn][20] , val[maxn];
ii edges[maxn];
bool isShop[maxn];
ll dfs(int u , int p)
{
in[u] = ++timer;
ll cur = linf;
if(isShop[u]) cur = val[u];
for(ii i : adj[u])
{
int v = i.fi;
ll w = i.se;
if(v != p)
{
depth[v] = depth[u] + 1;
val[v] = val[u] + w;
par[v][0] = u;
cur = min(cur , dfs(v , u));
}
}
if(cur != linf) mi[u][0] = cur - 2 * val[u];
out[u] = timer;
return cur;
}
void BuildLca()
{
for(int j = 1; (1 << j) <= n; j++)
{
for(int i = 1; i <= n; i++)
{
par[i][j] = par[par[i][j - 1]][j - 1];
mi[i][j] = min(mi[i][j - 1] , mi[par[i][j - 1]][j - 1]);
}
}
}
ll Jump(int d , int u)
{
int cur = u;
ll ans = linf;
for(int i = 0; (1 << i) <= d; i++)
{
if(bit(d , i))
{
ans = min(ans , mi[cur][i]);
cur = par[cur][i];
}
}
return min(ans , mi[cur][0]);
}
void solve(void)
{
cin >> n >> numshops >> q >> root;
for(int i = 1; i < n; i++)
{
int u , v , w;
cin >> u >> v >> w;
adj[u].push_back({v , w});
adj[v].push_back({u , w});
edges[i] = ii(u , v);
}
for(int i = 1; i <= numshops; i++)
{
int u; cin >> u;
isShop[u] = 1;
}
ms(mi , 0x3f);
dfs(root , -1);
BuildLca();
while(q--)
{
int id , u; cin >> id >> u;
int p;
if(depth[edges[id].fi] > depth[edges[id].se])
{
p = edges[id].fi;
}
else
{
p = edges[id].se;
}
if(in[p] <= in[u] && out[u] <= out[p])
{
ll tmp = Jump(depth[u] - depth[p] , u);
if(tmp == linf)
{
cout << "oo\n";
}
else
{
cout << tmp + val[u] << "\n";
}
}
else cout << "escaped\n";
}
}
/**
**/
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define task ""
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) solve();
// execute;
}
