import sys
input = sys.stdin.readline
from collections import *

def bfs(sta):
    dist = [10**18]*(2*N)
    dist[2*sta] = 0
    q = deque([2*sta])
    
    while q:
        v = q.popleft()
        
        for nv in G[v]:
            if dist[nv]==10**18:
                dist[nv] = dist[v]+1
                q.append(nv)
    
    return dist

N, M, P = map(int, input().split())
s, g = map(int, input().split())
s -= 1
g -= 1
G = [[] for _ in range(2*N)]

for _ in range(N-1):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    G[2*u].append(2*v+1)
    G[2*u+1].append(2*v)
    G[2*v].append(2*u+1)
    G[2*v+1].append(2*u)

dist1 = bfs(s)
dist2 = bfs(g)
ans = []

for i in range(N):
    if P%2==0 and min(dist1[2*i]+dist2[2*i], dist1[2*i+1]+dist2[2*i+1])<=P:
        ans.append(i)
    elif P%2==1 and min(dist1[2*i]+dist2[2*i+1], dist1[2*i+1]+dist2[2*i])<=P:
        ans.append(i)

if len(ans)==0:
    print(-1)
    exit()
    
print(len(ans))

for ans_i in ans:
    print(ans_i+1)