#include<bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
#define SPEED ios_base::sync_with_stdio(false); cin.tie(0), cout.tie(0)
#define rall(v) (v).rbegin(),(v).rend()
#define all(v) (v).begin(),(v).end()
#define setp fixed<<setprecision
#define OK cerr<<"OK"<<endl<<flush
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define F first
#define S second
#define y0 jahdakdh
#define y1 jahsadakdakdh
#define endl '\n'
const ll MOD=1e9+7;
const ll mod=(1ll<<31)-1;
const ld eps=1e-8;
const ll MAXLONG=9223372036854775807;
const ll MINLONG=-9223372036854775807;
using namespace std;
mt19937 rng(std::chrono::system_clock::now().time_since_epoch().count());
const int N=1e5+5;
struct edge
{
int p, u, w;
}e[N];
int n, s, q, root, par[N], tin[N], tout[N], tmr, up[N][18];
ll de[N], val[N], valup[N][18];
vector<pii>g[N];
bitset<N>shop;
void dfs(int v, int p)
{
tin[v]=++tmr;
par[v]=p;
if(!shop[v]) val[v]=MOD*MOD;
for(pii u : g[v])
{
if(u.F==p) continue;
de[u.F]=de[v]+u.S;
dfs(u.F, v);
if(val[u.F]!=MOD*MOD) val[v]=min(val[v], val[u.F]+u.S);
}
tout[v]=++tmr;
}
void calcup(int v, int p)
{
up[v][0]=p;
valup[v][0]=val[p];
for(int i=1; i<18; i++)
{
up[v][i]=up[up[v][i-1]][i-1];
valup[v][i]=min(valup[v][i-1], valup[up[v][i-1]][i-1]);
}
for(pii u : g[v])
if(u.F!=p) calcup(u.F, v);
}
inline bool anc(int v, int u)
{
return (tin[v]<=tin[u] and tout[u]<=tout[v]);
}
ll goup(int v, int p)
{
ll ret=MOD*MOD;
for(int i=17; i>=0; i--)
{
if(anc(p, up[v][i]))
{
ret=min(ret, valup[v][i]);
v=up[v][i];
}
}
return ret;
}
int main()
{
SPEED;
cin>>n>>s>>q>>root;
for(int i=1; i<n; i++)
{
cin>>e[i].p>>e[i].u>>e[i].w;
g[e[i].p].pb({e[i].u, e[i].w});
g[e[i].u].pb({e[i].p, e[i].w});
}
for(int i=0; i<s; i++)
{
int x; cin>>x;
shop[x]=1;
}
dfs(root, 0);
for(int i=1; i<=n; i++)
{
//cout<<"val = "<<i<<' '<<val[i]<<endl;
if(val[i]!=MOD*MOD) val[i]-=de[i];
//cout<<"val last = "<<i<<' '<<val[i]<<endl;
}
for(int i=1; i<n; i++)
if(par[e[i].p]==e[i].u) swap(e[i].u, e[i].p);
val[0]=MOD*MOD;
memset(valup, 63, sizeof(valup));
calcup(root, 0);
while(q--)
{
int idx, v;
cin>>idx>>v;
if(!anc(e[idx].u, v))
{
cout<<"escaped\n";
continue;
}
else
{
if(val[e[idx].u]==MOD*MOD)
{
cout<<"oo\n";
continue;
}
cout<<min(val[v]+de[v], goup(v, e[idx].u)+de[v])<<endl;
}
}
return 0;
}
