import sys
from collections import deque

def main():
    input = sys.stdin.read().split()
    ptr = 0
    N = int(input[ptr]); ptr += 1
    M = int(input[ptr]); ptr += 1
    P = int(input[ptr]); ptr += 1
    S = int(input[ptr]); ptr += 1
    G = int(input[ptr]); ptr += 1

    adj = [[] for _ in range(N + 1)]
    for _ in range(M):
        u = int(input[ptr]); ptr += 1
        v = int(input[ptr]); ptr += 1
        adj[u].append(v)
        adj[v].append(u)

    # Compute d_s (distance from S)
    d_s = [-1] * (N + 1)
    q = deque([S])
    d_s[S] = 0
    while q:
        u = q.popleft()
        for v in adj[u]:
            if d_s[v] == -1:
                d_s[v] = d_s[u] + 1
                q.append(v)

    # Compute d_g (distance from G)
    d_g = [-1] * (N + 1)
    q = deque([G])
    d_g[G] = 0
    while q:
        u = q.popleft()
        for v in adj[u]:
            if d_g[v] == -1:
                d_g[v] = d_g[u] + 1
                q.append(v)

    valid = []
    for u in range(1, N + 1):
        if d_s[u] == -1 or d_g[u] == -1:
            continue
        sum_d = d_s[u] + d_g[u]
        if sum_d > P:
            continue
        if (P - sum_d) % 2 != 0:
            continue
        parity_sum = (d_s[u] % 2) + (d_g[u] % 2)
        if parity_sum % 2 == P % 2:
            valid.append(u)

    if not valid:
        print(-1)
    else:
        valid.sort()
        print(len(valid))
        for u in valid:
            print(u)

if __name__ == '__main__':
    main()