#!/usr/bin/env python3

from itertools import combinations
import sys

n, m, k = map(int, input().split())
V = list(range(1, n + 1))
E = tuple(tuple(map(int, input().split())) for _ in range(m))
for r in range(1, k + 1):
    for U in map(set, combinations(V, r)):
        if sum(1 for e in E if e[0] in U or e[1] in U) == k:
            print(r)
            print(*U)
            sys.exit(0)
print("impossible")