object Main {
  import java.io.{BufferedReader, InputStream, InputStreamReader}
  import java.util.StringTokenizer
  import scala.reflect.ClassTag

  def main(args: Array[String]): Unit = {
    val out = new java.io.PrintWriter(System.out)
    new Main(out, new InputReader(System.in)).solve()
    out.flush()
  }

  private val oj = System.getenv("ATCODER_DEBUG") == null
  def DEBUG(f: => Unit): Unit = {
    if (!oj){ f }
  }
  def debug(as: Array[Boolean]): Unit = if (!oj){ debug(as.map(x => if(x) "1" else "0").mkString) }
  def debug(as: Array[Int]): Unit = if (!oj){ debug(as.mkString(" ")) }
  def debug(as: Array[Long]): Unit =if (!oj){ debug(as.mkString(" ")) }
  def debugDim(m: Array[Array[Long]]): Unit = if (!oj){
    REP(m.length) { i =>
      debug(m(i))
    }
  }
  def debugDimFlip(m: Array[Array[Long]]): Unit = if (!oj){
    REP(m(0).length) { j =>
      REP(m.length) { i =>
        System.err.print(m(i)(j))
        System.err.print(" ")
      }
      System.err.println()
    }
  }
  def debug(s: => String): Unit = DEBUG {
    System.err.println(s)
  }
  def debugL(num: => Long): Unit = DEBUG {
    System.err.println(num)
  }

  class InputReader(val stream: InputStream) {
    private val reader = new BufferedReader(new InputStreamReader(stream), 32768)
    private var tokenizer: StringTokenizer = _

    def next(): String = {
      while (tokenizer == null || !tokenizer.hasMoreTokens)
        tokenizer = new StringTokenizer(reader.readLine)
      tokenizer.nextToken
    }

    def nextInt(): Int = Integer.parseInt(next())
    def nextLong(): Long = java.lang.Long.parseLong(next())
    def nextChar(): Char = next().charAt(0)

    def ni(): Int = nextInt()
    def nl(): Long = nextLong()
    def nc(): Char = nextChar()
    def ns(): String = next()
    def ns(n: Int): Array[Char] = ns().toCharArray
    def na(n: Int, offset: Int = 0): Array[Int] = map(n)(_ => ni() + offset)
    def na2(n: Int, offset: Int = 0): (Array[Int], Array[Int]) = {
      val A1, A2 = Array.ofDim[Int](n)
      REP(n) { i =>
        A1(i) = ni() + offset
        A2(i) = ni() + offset
      }
      (A1, A2)
    }
    def nm(n: Int, m: Int): Array[Array[Int]] = {
      val A = Array.ofDim[Int](n, m)
      REP(n) { i =>
        REP(m) { j =>
          A(i)(j) = ni()
        }
      }
      A
    }
    def nal(n: Int): Array[Long] = map(n)(_ => nl())
    def nm_c(n: Int, m: Int): Array[Array[Char]] = map(n) (_ => ns(m))
  }

  def REP(n: Int, offset: Int = 0)(f: Int => Unit): Unit = {
    var i = offset
    val N = n + offset
    while(i < N) { f(i); i += 1 }
  }
  def REP_r(n: Int, offset: Int = 0)(f: Int => Unit): Unit = {
    var i = n - 1 + offset
    while(i >= offset) { f(i); i -= 1 }
  }
  def TO(from: Int, to: Int)(f: Int => Unit): Unit = {
    REP(to - from + 1, from) { i =>
      f(i)
    }
  }
  def map[@specialized A: ClassTag](n: Int, offset: Int = 0)(f: Int => A): Array[A] = {
    val res = Array.ofDim[A](n)
    REP(n)(i => res(i) = f(i + offset))
    res
  }

  def sumL(as: Array[Int]): Long = {
    var s = 0L
    REP(as.length)(i => s += as(i))
    s
  }
  def cumSum(as: Array[Int]): Array[Long] = {
    val cum = Array.ofDim[Long](as.length + 1)
    REP(as.length) { i =>
      cum(i + 1) = cum(i) + as(i)
    }
    cum
  }
}

class Main(out: java.io.PrintWriter, sc: Main.InputReader) {
  import sc._
  import Main._
  import java.util.Arrays.sort

  import scala.collection.mutable
  import math.{abs, max, min}
  import mutable.ArrayBuffer

  // toIntとか+7とかするならvalにしろ
  @inline private def MOD = 1000000007

  case class Edge(i: Int, a: Int, b: Int) {
    def oppo(v: Int) = if (a == v) b else a
  }
  case class Entry(v: Int, deg: Int) extends Comparable[Entry] {
    override def compareTo(o: Entry): Int = Integer.compare(deg, o.deg)
  }

  def solve2(): Boolean = {
    val N, M = ni()
    if (M % 2 == 1) return false

    val deg = Array.ofDim[Int](N)
    val E = Array.ofDim[Edge](M)
    val g = Array.fill[mutable.Set[Int]](N)(mutable.Set()) //edge番号
    REP(M) { i =>
      val a, b = ni() - 1
      E(i) = Edge(i, a, b)
      deg(a) += 1
      deg(b) += 1
      g(a) += i
      g(b) += i
    }

    val q = new java.util.PriorityQueue[Entry]
    def addEntry(v: Int): Unit = {
      if (deg(v) > 1) q.add(Entry(v, deg(v)))
    }

    debug(deg)

    REP(N) { i =>
      addEntry(i)
    }

    val ans = ArrayBuffer[(Int, Int)]()

    // v -> e1, v -> e2
    def outward2(v: Int, e1: Edge): Unit = {
      g(v).remove(e1.i)
      g(E(e1.i).oppo(v)).remove(e1.i)
      val e2 = E(g(v).head)
      g(v).remove(e2.i)
      g(E(e2.i).oppo(v)).remove(e2.i)

      debug(s"outward2($v) e1:$e1 e2:$e2")

      deg(v) -= 2
      deg(e1.oppo(v)) -= 1
      deg(e2.oppo(v)) -= 1

      addEntry(v)
      addEntry(e1.oppo(v))
      addEntry(e2.oppo(v))

      ans += v -> e1.oppo(v)
      ans += v -> e2.oppo(v)
    }

    // e1 -> v -> e2
//    def passOver(v: Int): Unit = {
//      val e1 = E(g(v).head)
//      g(v).remove(e1.i)
//      g(E(e1.i).oppo(v)).remove(e1.i)
//      val e2 = E(g(v).head)
//      g(v).remove(e2.i)
//      g(E(e2.i).oppo(v)).remove(e2.i)
//
//      debug(s"passOver($v) e1:$e1 e2:$e2")
//
//      deg(v) -= 2
//      deg(e1.oppo(v)) -= 1
//      deg(e2.oppo(v)) -= 1
//
//      addEntry(v)
//      addEntry(e1.oppo(v))
//      addEntry(e2.oppo(v))
//
//      ans += e1.oppo(v) -> v
//      ans += v -> e2.oppo(v)
//    }

    while(!q.isEmpty) {
      val e = q.poll()
      if (deg(e.v) == e.deg) {
        e.deg match {
//          case 1 =>
//            val edge = E(g(e.v).head)
//            val u = edge.oppo(e.v)
//            outward2(u, edge)

          case _ =>
            outward2(e.v, E(g(e.v).head))

//          case 3 =>
//            passOver(e.v)
        }
      }
    }

    assert(ans.length == M)
    REP(M) { i =>
      val e = ans(i)
      out.println(s"${e._1+1} ${e._2+1}")
    }

    true
  }

  def solve(): Unit = {
    if (!solve2()) out.println(-1)
  }
}