#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define MAXN 100005
#define ii pair<int,int>
#define bit(i,j) ((i>>j)&1)
#define sz(i) (int)i.size()
#define endl '\n'
using namespace std;
const ll INF = 1e18 + 7;
int n, m, ntest, root;
int a[MAXN];
ii edge[MAXN];
vector<ii>g[MAXN];
namespace sub1
{
int timedfs;
int h[MAXN],f[MAXN][18];
ll dp[MAXN], s[MAXN],val[MAXN][18];
ii range[MAXN];
void init(int u, int p)
{
if(a[u])
dp[u] = s[u];
for(ii i : g[u])
{
int v = i.F, w = i.S;
if(v == p)
continue;
s[v] = s[u] + w;
init(v, u);
dp[u]=min(dp[u],dp[v]);
}
}
void dfs(int u, int p)
{
range[u].F = ++timedfs;
h[u] = h[p] + 1;
f[u][0] = p;
val[u][0] = dp[p] - 2 * s[p];
for(int i = 1; i <= 16; i++)
{
f[u][i] = f[f[u][i - 1]][i - 1];
val[u][i] = min(val[u][i - 1], val[f[u][i - 1]][i - 1]);
}
for(ii i : g[u])
{
int v = i.F;
if(v == p)
continue;
dfs(v, u);
}
range[u].S = timedfs;
}
void ans(int u, int v)
{
int delta = h[u] - h[v], curu = u;
ll res = dp[u]-2*s[u];
for(int i = 0; i <= log2(delta); i++)
if(bit(delta, i))
{
res = min(res, val[u][i]);
u = f[u][i];
}
if(res + s[curu] > 1e14)
return cout << "oo\n", void();
cout << res + s[curu] << endl;
}
bool check(int u, int v, int x)
{
if(range[x].F >= range[u].F && range[x].F <= range[u].S && range[x].F >= range[v].F && range[x].F <= range[v].S)
return 0;
return 1;
}
void solve()
{
for(int i = 1; i <= n; i++)
{
dp[i] = INF;
for(int j = 0; j <= 16; j++)
val[i][j] = INF;
}
init(root, 0);
dfs(root, 0);
while(ntest--)
{
int id, u;
cin >> id >> u;
if(check(edge[id].F, edge[id].S, u))
cout << "escaped\n";
else if(h[edge[id].F] > h[edge[id].S])
ans(u, edge[id].F);
else
ans(u, edge[id].S);
}
}
}
main()
{
if(fopen("TEST.inp","r"))
{
freopen("TEST.inp","r",stdin);
freopen("TEST.out","w",stdout);
}
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> ntest >> root;
for(int i = 1; i < n; i++)
{
int x, y, z;
cin >> x >> y >> z;
edge[i] = {x, y};
g[x].push_back({y, z});
g[y].push_back({x, z});
}
for(int i = 1; i <= m; i++)
{
int x;
cin >> x;
a[x] = 1;
}
sub1::solve();
}
/**
10 2 1 9
7 1 3
9 2 3
10 5 1
8 7 3
10 1 3
5 6 2
2 1 2
3 1 1
4 2 2
2
7
7 3
**/
