#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC optimize("conserve-stack")
#include<bits/stdc++.h>
#define int long long
#define ll long long
#define down cout<<'\n';
#define debug cout<<" cucuucucuuu",down
#define NHP ios_base::sync_with_stdio(0);cout.tie(0);cin.tie(0);
#define modwwe int t;cin>>t; while(t--)
#define bit(i,j) (i>>j&1)
#define sobit(a) __builtin_popcountll(a)
#define task "test"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define pb push_back
#define mask(i) (1<<i)
#define checktime cerr << (double)clock() / CLOCKS_PER_SEC * 1000 << " ms";
using namespace std;
#define getchar_unlocked getchar
inline int scan()
{
char c = getchar_unlocked();
int x = 0;
while (c < '0' || c > '9')
{
c = getchar_unlocked();
}
while (c >= '0' && c <= '9')
{
x = (x << 1) + (x << 3) + c - '0';
c = getchar_unlocked();
}
return x;
};
void phongbeo();
const int inf = 1e18;
const int mod2 = 1e9+7;
const int mod1 = 998244353;
int add(int x,int y)
{
if(x+y>=mod2) x-=mod2;
if(x+y<0) x+=mod2;
return x+y;
}
struct icd
{
long double a;
int b;
};
struct ib
{
int a;
int b;
};
struct ic
{
int a, b, c, d;
};
struct ie
{
int a, b, c, d, e;
};
int n, m, s1, s2, s4, s3, sf, k, s5, s6, mx, s7, s8, s9, mx2, res, dem2 = 0, dem = 0, s33, dem3, dem4, mid, l2, r2, center;
int i, s10, s12,k1,k2,k3,s11,limit,w,l,r,last,root;
int kk,invf;
int el = 19;
main()
{
if(fopen(task".inp","r"))
{
fin(task);
fou(task);
}
NHP
/// cin>>s1;
//modwwe
phongbeo(),down
// checktime
}
vector<ib> v[500001];
ib a[500001];
int dep[500001];
int dp[500001];
int st[17][500001];
int par[17][500001];
int in[500001];
int ou[500001];
int deptrai(int x)
{
if(par[0][a[x].b]==a[x].a) return a[x].b;
return a[x].a;
}
bool check(int x,int y)
{
if(in[x]<=in[y]&&ou[x]>=in[y]) return 1;
return 0;
}
void dfs(int x,int y)
{
in[x]=++dem;
for(auto f:v[x])
if(f.a!=y)
{
dep[f.a]=dep[x]+f.b;
dfs(f.a,x);
dp[x]=min(dp[x],dp[f.a]+f.b);
}
par[0][x]=y;
st[0][x]=dp[x]-dep[x];
ou[x]=dem;
}
void phongbeo()
{
cin>>n>>k>>m>>root;
for(int i=1;i<n;i++)
cin>>a[i].a>>a[i].b>>s2,
v[a[i].a].pb({a[i].b,s2}),
v[a[i].b].pb({a[i].a,s2});
for(int i=1;i<=n;i++)
dp[i]=inf;
for(int i=1;i<=k;i++)
cin>>l,dp[l]=0;
dfs(root,0);
ou[0]=dem;
for(int i=1;i<17;i++)
for(int j=1;j<=n;j++)
par[i][j]=par[i-1][par[i-1][j]],
st[i][j]=min(st[i-1][j],st[i-1][par[i-1][j]]);
for(int i=1;i<=m;i++)
{
cin>>l>>r;
l=deptrai(l);
s10=dep[r];
if(!check(l,r))cout<<"escaped";
else
{
s2=inf;
for(int j=16;j>=0;--j)
if(check(l,par[j][r]))
{
s2=min(s2,st[j][r]);
r=par[j][r];
}
s2=min(s2,st[0][r]);
if(s2>=1e14)cout<<"oo";
else cout<<s2+s10;
}
down
}
}
