import sys
N, K, INF, W = 10**5+5, 17, 10**18, 200
sys.setrecursionlimit(N)
adj, cost = [[[] for i in range(N)] for j in range(2)]
is_shop, depth, root_dist, shop_dist = [[0 for i in range(N)] for j in range(4)]
st, par = [[[0 for i in range(N)] for j in range(K)] for k in range(2)]
n, s, q, e = [int(_) for _ in input().split()]
edges = []
def dfs(u, p = -1):
shop_dist[u] = 0 if is_shop[u] else INF
for i in range(len(adj[u])):
v = adj[u][i]
if v == p:
continue
par[0][v] = u
depth[v] = depth[u]+1;
root_dist[v] = root_dist[u]+cost[u][i]
dfs(v,u)
shop_dist[u] = min(shop_dist[u],shop_dist[v]+cost[u][i])
def get_block(ind):
u,v = edges[ind-1]
return u if depth[u] > depth[v] else v
def prep_lca():
for u in range(1,n+1):
st[0][u] = min(shop_dist[u],shop_dist[par[0][u]])
for s in range(1,K-1):
for u in range(1,n+1):
par[s][u] = par[s-1][par[s-1][u]]
st[s][u] = min(st[s-1][u],st[s-1][par[s-1][u]])
def get_lca(u,v):
if depth[u] < depth[v]:
u,v = v,u
for k in range(K-1,-1,-1):
if depth[par[k][u]] >= depth[v]:
u = par[k][u]
if u == v:
return u
for k in range(K-1,-1,-1):
if par[k][u] != par[k][v]:
u, v = par[k][u], par[k][v]
return par[0][u]
def solve(u, block):
lca = get_lca(u,block)
if lca != block:
return "escaped";
v = u
ans = shop_dist[v]
for k in range(K-1,-1,-1):
if depth[par[k][v]] >= depth[block]:
ans = min(ans,st[k][v])
v = par[k][v]
if ans == INF:
return "oo"
return ans + root_dist[u]
for i in range(n-1):
a,b,w = [int(_) for _ in input().split()]
adj[a].append(b)
adj[b].append(a)
cost[a].append(w)
cost[b].append(w)
edges.append([a,b])
for i in range(s):
is_shop[int(input())] = True
depth[e] = 1
dfs(e)
for i in range(1,n+1):
if shop_dist[i] != INF:
shop_dist[i] -= root_dist[i]
prep_lca()
for i in range(q):
ind,u = [int(x) for x in input().split()]
block = get_block(ind)
print(solve(u,block))
