import kotlin.math.ceil

fun main() {
    val (n, m, k) = readInts()
    val g = List(n) { mutableListOf<Int>() }
    repeat(m) {
        val (a, b) = readInts()
        g[a-1].add(b-1)
        g[b-1].add(a-1)
    }
    val deg = IntArray(g.size) { g[it].size }
    val ans = mutableListOf<Int>()
    val ds = g.indices.sortedBy { deg[it] }
    fun go(curTot: Int) : Boolean {
        if (curTot == k) return true
        for (i in ds) {
            if (curTot + deg[i] > k || i in ans) continue
            ans.add(i)
            for (j in g[i]) {
                deg[j]--
            }
            if (go(curTot + deg[i])) return true
            for (j in g[i]) {
                deg[j]++
            }
            ans.removeLast()
        }
        return false
    }
    if (m >= k && go(0)) {
        println(ans.size)
        println(ans.joinToString(" ") { (it + 1).toString() })
    } else {
        println("impossible")
    }
}

private fun readInt() = readln().toInt()
private fun readLongs() = readStrings().map { it.toLong() }
private fun readStrings() = readln().split(" ")
private fun readInts() = readStrings().map { it.toInt() }