#include <bits/stdc++.h>
#define N 300005
#define ll long long int
#define MP make_pair
#define pb push_back
#define ppb pop_back
#define sp " "
#define endl "\n"
#define fi first
#define se second
#define ii pair<int,int>
#define lli pair<ll,ll>
#define fast cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(false)
#define fast2 freopen ("badhair.gir","r",stdin);freopen ("badhair.cik","w",stdout);
#define mod 1000000007
#define fs(x,y) for(ll i=1;i<=y;i++) cin>>x[i]
#define fo(i,x,y) for(ll i=x;i<=y;i++)
#define INF 1000000000005
#define ull unsigned long long int
using namespace std;
ll n,m,ar[N],sum,t,s,q,e,dist[N],mark[N],magic[N],jumpvertex[N][30],jumpmagic[N][30],shop[N],cnt,tut[N],dp[N],ilk[N],pw[N];
lli tree[10*N],edg[N];
vector<lli> v[N];
void f1(ll ind,ll back,ll dst)
{
dist[ind]=dst;
tut[++cnt]=ind;
ilk[ind]=cnt;
dp[ind]=1e17;
jumpvertex[ind][0]=back;
fo(i,1,20)
{
jumpvertex[ind][i]=jumpvertex[jumpvertex[ind][i-1]][i-1];
}
if(shop[ind])
dp[ind]=dst;
// jumpmagic[ind][0]=-2*dst+dp[ind];
// fo(i,1,20)
// {
// jumpmagic[ind][i]=min(jumpmagic[ind][i-1],jumpmagic[jumpvertex[ind][i-1]][i-1]);
// }
for(int i=0;i<v[ind].size();i++)
{
ll a=v[ind][i].fi;
ll b=v[ind][i].se;
if(a==back)
continue;
f1(a,ind,dst+b);
tut[++cnt]=ind;
if(dp[a]<1e17)
dp[ind]=min(dp[ind],dp[a]);
}
magic[ind]=-2*dst+dp[ind];
if(dp[ind]==1e17)
magic[ind]=1e17;
}
void f2(int ind,int back,int dst)
{
jumpmagic[ind][0]=magic[ind];
fo(i,1,20)
{
jumpmagic[ind][i]=min(jumpmagic[ind][i-1],jumpmagic[jumpvertex[ind][i-1]][i-1]);
}
for(int i=0;i<v[ind].size();i++)
{
ll a=v[ind][i].fi;
ll b=v[ind][i].se;
if(a==back)
continue;
f2(a,ind,dst+b);
}
}
void build(int ind,int l,int r)
{
if(l==r)
{
tree[ind]={dist[tut[l]],tut[l]};
return;
}
int mid=(l+r)/2;
build(ind*2,l,mid);
build(ind*2+1,mid+1,r);
tree[ind]=min(tree[ind*2],tree[ind*2+1]);
}
lli query(int ind,int l,int r,int a,int b)
{
if(l>b || r<a)
return {1e17,0};
if(l>=a && r<=b)
return tree[ind];
int mid=(l+r)/2;
return min(query(ind*2,l,mid,a,b),query(ind*2+1,mid+1,r,a,b));
}
ll lca(ll a,ll b)
{
return query(1,1,cnt,min(ilk[a],ilk[b]),max(ilk[a],ilk[b])).se;
}
int main()
{
fast;
// cout<<endl<<endl;
cin>>n>>s>>q>>e;
pw[0]=1;
fo(i,1,20)
pw[i]=pw[i-1]*2;
fo(i,1,n-1)
{
ll a,b,c;
cin>>a>>b>>c;
edg[i]={a,b};
v[a].pb({b,c});
v[b].pb({a,c});
}
fo(i,1,s)
{
int a;
cin>>a;
shop[a]=1;
}
f1(e,e,0);
f2(e,e,0);
// fo(i,1,n)
// cout<<i<<sp<<magic[i]<<endl;
build(1,1,cnt);
// cout<<cnt<<endl;
// fo(i,1,cnt)
// cout<<tut[i]<<sp;
// cout<<endl;
fo(i,1,q)
{
int a,b;
cin>>a>>b;
int x=edg[a].fi;
int y=edg[a].se;
if(lca(x,b)!=x || lca(y,b)!=y)
{
cout<<"escaped"<<endl;
continue;
}
ll z=dist[b];
// cout<<z<<sp;
z-=max(dist[x],dist[y]);
// cout<<++z<<sp;
sum=1e17;
int ind=b;
for(int j=20;j>=0;j--)
{
if(pw[j]<=z)
{
z-=pw[j],sum=min(sum,jumpmagic[ind][j]);
ind=jumpvertex[ind][j];
}
}
if(sum>=1e17)
{
cout<<"oo"<<endl;
continue;
}
cout<<sum+dist[b]<<endl;
}
// cout<<endl<<endl;
// fo(i,1,n)
// {
// cout<<i<<": ";
// for(int j=0;j<=2;j++)
// cout<<jumpmagic[i][j]<<sp;
// cout<<endl;
// cout<<i<<": ";
// for(int j=0;j<=2;j++)
// cout<<jumpvertex[jumpvertex[i][j-1]][j-1]<<sp;
// cout<<endl;
// cout<<endl;
// }
}
