#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 1023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<int, ll> il;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));
#define mod 1000000007
inline int add(int a,int b){
int r=a+b;
while(r>=mod)r-=mod;
while(r<0)r+=mod;
return r;
}
inline int mult(int a,int b){
return (int)(((ll)(a*b))%mod);
}
inline int rd(){
int x=0;
char ch=getchar_unlocked();
while(!(ch&16))ch=getchar();//keep reading while current character is whitespace
while(ch&16){//this will break when ‘\n’ or ‘ ‘ is encountered
x=(x<<3)+(x<<1)+(ch&15);
ch=getchar_unlocked();
}
return x;
}
#define maxn 100005
struct node{
int n;
vector<ll> lz;
vector<il> v;
void init(int _n){
n=_n;
v.resize(4*n,{0,0});
lz.resize(4*n,0);
}
void ppo(int i,int s,int e){
v[i].se+=lz[i];
if(s!=e){
lz[2*i+1]+=lz[i];
lz[2*i+2]+=lz[i];
}
lz[i]=0;
}
void up(int i,int s,int e,int x,int y,ll nv){
if(s==x&&e==y){
lz[i]+=nv;return;
}
int m=(s+e)>>1;
if(y<=m)up(2*i+1,s,m,x,y,nv);
else if(x>m)up(2*i+2,m+1,e,x,y,nv);
else up(2*i+1,s,m,x,m,nv),up(2*i+2,m+1,e,m+1,y,nv);
ppo(2*i+1,s,m);ppo(2*i+2,m+1,e);
v[i]=min(v[2*i+1],v[2*i+2]);
}
void up(int x,int y,ll nv){
up(0,0,n-1,x,y,nv);
}
void set(int i,int s,int e,int x,int t){
if(s==x&&e==x){
v[i].fi=t;return;
}
int m=(s+e)>>1;
if(x<=m)set(2*i+1,s,m,x,t);
else set(2*i+2,m+1,e,x,t);
ppo(2*i+1,s,m);ppo(2*i+2,m+1,e);
v[i]=min(v[2*i+1],v[2*i+2]);
}
void set(int x,int t){
set(0,0,n-1,x,t);
}
il qry(int i,int s,int e,int x,int y){
ppo(i,s,e);
if(s==x&&e==y)return v[i];
int m=(s+e)>>1;
if(y<=m)return qry(2*i+1,s,m,x,y);
if(x>m)return qry(2*i+2,m+1,e,x,y);
return min(qry(2*i+1,s,m,x,m),qry(2*i+2,m+1,e,m+1,y));
}
il qry(int x,int y){
if(x>y)return {2,LINF};
return qry(0,0,n-1,x,y);
}
}seg[maxn];
int n,q,s,e,w[maxn],sub[maxn];
vii AL[maxn];
bool shop[maxn],done[maxn];
vi nodeComp[maxn],edgeComp[maxn];
vii nodeRange[maxn],edgeRange[maxn];
ii block[maxn];
int cnt;
void calc(int u,int p){
sub[u]=1;
for(auto[v,i]:AL[u]){
if(v==p||done[v])continue;
calc(v,u);
sub[u]+=sub[v];
}
}
void dfs(int u,int p,int c){
ii rng={cnt,cnt};++cnt;
for(auto[v,i]:AL[u]){
if(v==p||done[v])continue;
dfs(v,u,c);
ii tmp=nodeRange[v].back();
rng.se=max(rng.se,tmp.se);
edgeComp[i].pb(c);
edgeRange[i].pb(tmp);
}
nodeComp[u].pb(c);
nodeRange[u].pb(rng);
}
void decomp(int u){
calc(u,-1);
int c=u;
while(true){
bool val=true;
for(auto[v,i]:AL[c]){
if(done[v])continue;
if(sub[v]<sub[c]&&sub[v]>sub[u]/2){
c=v;val=false;
}
}
if(val)break;
}
cnt=0;
dfs(c,-1,c);
seg[c].init(cnt);
done[c]=true;
for(auto[v,i]:AL[c]){
if(!done[v])decomp(v);
}
}
int main(){
n=rd();s=rd();q=rd();e=rd();
for(int i=1;i<n;++i){
int a=rd(),b=rd();
w[i]=rd();
AL[a].pb({b,i});
AL[b].pb({a,i});
}
for(int i=0;i<s;++i){
int c=rd();
shop[c]=true;
}
decomp(1);
for(int i=1;i<n;++i){
for(int j=0;j<sz(edgeComp[i]);++j){
int c=edgeComp[i][j];
ii r=edgeRange[i][j];
seg[c].up(r.fi,r.se,w[i]);
}
}
for(int i=1;i<=n;++i){
for(int j=0;j<sz(nodeComp[i]);++j){
int c=nodeComp[i][j];
ii r=nodeRange[i][j];
if(i==e)seg[c].set(r.fi,0);
else if(shop[i])seg[c].set(r.fi,1);
else seg[c].set(r.fi,2);
}
}
for(int i=1;i<=n;++i)block[i]={seg[i].n,-1};
for(int i=0;i<q;++i){
int x=rd(),s=rd();
for(int i=0;i<sz(edgeComp[x]);++i){
block[edgeComp[x][i]]=edgeRange[x][i];
}
ll ans=LINF;
for(int i=0;i<sz(nodeComp[s]);++i){
int c=nodeComp[s][i];
ii r=nodeRange[s][i];
if(block[c].fi<=r.fi&&r.fi<=block[c].se)continue;//path to this is blocked
il d1=seg[c].qry(r.fi,r.fi);
if(d1.fi==0)ans=-1;
else if(d1.fi==1)ans=min(ans,0ll);
il d2=min(seg[c].qry(0,block[c].fi-1),seg[c].qry(block[c].se+1,seg[c].n-1));
if(d2.fi==0)ans=-1;
else if(d2.fi==1)ans=min(ans,d1.se+d2.se);
}
for(int i=0;i<sz(edgeComp[x]);++i){
int c=edgeComp[x][i];
block[c]={seg[c].n,-1};
}
if(ans==LINF)pf("oo\n");
else if(ans==-1)pf("escaped\n");
else pf("%lld\n",ans);
}
}
/*
5 2 3 1
1 2 3
1 3 2
3 4 1
3 5 2
2
4
2 2
2 5
4 5
*/
