import sys,collections,heapq

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


class Dijkstra:
    def __init__(self):
        self.e = collections.defaultdict(list)

    def add(self, u, v, d, directed=False):
        if directed is False:  # 無向グラフの場合
            self.e[u].append([v, d])
            self.e[v].append([u, d])
        else:  # 有向グラフの場合
            self.e[u].append([v, d])

    def delete(self, u, v):
        self.e[u] = [_ for _ in self.e[u] if _[0] != v]
        self.e[v] = [_ for _ in self.e[v] if _[0] != u]

    def search(self, s):  # sから各頂点までの最短距離
        d = collections.defaultdict(lambda: float('inf'))
        d[s] = 0
        q = []
        heapq.heappush(q, (0, s))
        v = collections.defaultdict(bool)
        while len(q):
            k, u = heapq.heappop(q)
            if v[u]:
                continue
            v[u] = True

            for uv, ud in self.e[u]:
                if v[uv]:
                    continue
                vd = k + ud
                if d[uv] > vd:
                    d[uv] = vd
                    heapq.heappush(q, (vd, uv))
        return d


N,M,P = MI()
S,G = MI()

Di = Dijkstra()

for _ in range(M):
    u,v = MI()
    Di.add((u,0),(v,1),1,directed=False)
    Di.add((u,1),(v,0),1,directed=False)

dist_S = Di.search((S,0))
dist_G = Di.search((G,0))

ANS = []
for i in range(1,N+1):
    if P % 2 == 0:
        d0 = dist_S[(i,0)]+dist_G[(i,0)]
        d1 = dist_S[(i,1)]+dist_G[(i,1)]
        if (d0 != float('inf') and d0 <= P) or (d1 != float('inf') and d1 <= P):
            ANS.append(i)
    else:
        d0 = dist_S[(i,0)]+dist_G[(i,1)]
        d1 = dist_S[(i,1)]+dist_G[(i,0)]
        if (d0 != float('inf') and d0 <= P) or (d1 != float('inf') and d1 <= P):
            ANS.append(i)

if ANS:
    print(len(ANS)) 
    print(*ANS,sep='\n')
else:
    print(-1)

# bfsの方が速く解ける