// https://atcoder.jp/contests/agc035/tasks/agc035_b

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"os"
	"reflect"
	"runtime"
	"sort"
	"strconv"
	"strings"
)

type UnionFind struct {
	// for children, the value is its parent index. for root, the value is -1 * the size of the group
	parents []int
}

func NewUnionFind(n int) *UnionFind {
	uf := &UnionFind{}

	uf.parents = make([]int, n)

	for i := range uf.parents {
		uf.parents[i] = -1
	}

	return uf
}

func (uf *UnionFind) root(x int) int {
	if uf.parents[x] < 0 {
		return x
	}

	r := uf.root(uf.parents[x])
	uf.parents[x] = r
	return r
}

func (uf *UnionFind) same(x, y int) bool {
	return uf.root(x) == uf.root(y)
}

func (uf *UnionFind) merge(x, y int) {
	xr := uf.root(x)
	yr := uf.root(y)

	if xr == yr {
		return
	}

	// make less index one as a root
	if xr > yr {
		xr, yr = yr, xr
	}

	uf.parents[xr] += uf.parents[yr]
	uf.parents[yr] = xr
}

func (uf *UnionFind) size(x int) int {
	return -uf.parents[uf.root(x)]
}

func (uf *UnionFind) groupCount() (res int) {
	for _, parent := range uf.parents {
		if parent < 0 {
			res++
		}
	}

	return
}

// コストを考えない Kruskal
func GetMinEdgeList(edgeList [][]int) [][]int {
	uf := NewUnionFind(len(edgeList))

	minEdgeList := make([][]int, len(edgeList))
	for i := range minEdgeList {
		minEdgeList[i] = make([]int, 0)
	}

	for u, uEdges := range edgeList {
		for _, v := range uEdges {
			if u > v || uf.same(u, v) {
				continue
			}

			minEdgeList[u] = append(minEdgeList[u], v)
			minEdgeList[v] = append(minEdgeList[v], u)
			uf.merge(u, v)
		}
	}

	return minEdgeList
}

// big - small. small はソートされている必要がある
func edgeListDiff(big [][]int, small [][]int) [][]int {
	res := make([][]int, len(big))

	for i := range res {
		res[i] = make([]int, 0)
	}

	for u, uEdgeList := range big {
		for _, v := range uEdgeList {
			i := sort.SearchInts(small[u], v)

			if i < len(small[u]) && small[u][i] == v {
				continue
			}

			res[u] = append(res[u], v)
		}
	}

	return res
}

// d: debug IO. it can print debug in test.
func solve(io *Io, d *Io) {
	N := io.NextInt()
	M := io.NextInt()

	edgeList := make([][]int, N)
	for i := range edgeList {
		edgeList[i] = make([]int, 0)
	}

	for i := 0; i < M; i++ {
		a := io.NextInt() - 1
		b := io.NextInt() - 1
		edgeList[a] = append(edgeList[a], b)
		edgeList[b] = append(edgeList[b], a)
	}

	// 1. 最小全域木を作る
	// 2. それ以外の辺については適当に方向を決めてしまう
	// 3. 最小全域木について根を適当に設けて、木の子から向きを確定させていく

	// 1. 最小全域木を作る
	minEdgeList := GetMinEdgeList(edgeList)

	for _, uEdges := range minEdgeList {
		sort.Ints(uEdges)
	}

	notMinEdgeList := edgeListDiff(edgeList, minEdgeList)

	resEdgeList := make([][]int, N)
	for u := range resEdgeList {
		resEdgeList[u] = make([]int, 0)
	}

	// 2. それ以外の辺については適当に方向を決めてしまう
	for u, uEdges := range notMinEdgeList {
		for _, v := range uEdges {
			if u > v {
				continue
			}

			// u -> v
			resEdgeList[u] = append(resEdgeList[u], v)
		}
	}

	// 3. 最小全域木について根を適当に設けて、木の子から向きを確定させていく
	var rec func(u, p int)

	rec = func(u, p int) {
		_ = edgeList[0]
		for _, v := range minEdgeList[u] {
			if v == p {
				continue
			}

			rec(v, u)
		}

		if p == -1 {
			return
		}

		curOutCt := len(resEdgeList[u])
		var from, to int

		if curOutCt%2 == 1 {
			from, to = u, p
		} else {
			from, to = p, u
		}

		resEdgeList[from] = append(resEdgeList[from], to)
	}

	rec(0, -1)

	if len(resEdgeList[0])%2 != 0 {
		io.Println(-1)
		return
	}

	for u, uEdges := range resEdgeList {
		for _, v := range uEdges {
			io.Println(u+1, v+1)
		}
	}
}

func main() {
	io := NewIo()
	defer io.Flush()
	solve(io, nil)
}

/* IO Helpers */

// Io combines reader, writer, & tokens as the state when processing the input
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

// NewIo creates Io with Stdin & Stdout
func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

// Flush calls the writer's Flush
func (io *Io) Flush() {
	io.writer.Flush()
}

// NextLine returns the string from reader.ReadLine()
func (io *Io) NextLine() string {
	if io.nextToken < len(io.tokens) {
		panic("io.nextToken < len(io.tokens)")
	}

	var buffer bytes.Buffer

	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buffer.Write(line)
		if !isPrefix {
			break
		}
	}

	return buffer.String()
}

// NextLines returns []string from next n lines
func (io *Io) NextLines(n int) []string {
	res := make([]string, n)
	for i := 0; i < n; i++ {
		res[i] = io.NextLine()
	}
	return res
}

// Next returns the string token (partial string of the line divided by spaces)
func (io *Io) Next() string {
	if io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}

	res := io.tokens[io.nextToken]
	io.nextToken++
	return res
}

// NextStrings returns the []string from the next n tokens
func (io *Io) NextStrings(n int) []string {
	res := make([]string, n)
	for i := 0; i < n; i++ {
		res[i] = io.Next()
	}
	return res
}

// NextRunes returns next string as []rune
func (io *Io) NextRunes() []rune {
	return []rune(io.Next())
}

// NextInt returns the int from the next token
func (io *Io) NextInt() int {
	res, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return res
}

// NextInts returns the []int from the next n tokens
func (io *Io) NextInts(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = io.NextInt()
	}
	return res
}

// NextFloat returns the float64 from the next token
func (io *Io) NextFloat() float64 {
	res, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return res
}

// NextFloats returns the []float64 from the next n tokens
func (io *Io) NextFloats(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = io.NextFloat()
	}
	return res
}

// Println prints the input to the writer in an easy-to-see form
func (io *Io) Println(a ...interface{}) {
	var values []string
	for i := 0; i < len(a); i++ {
		values = append(values, "%v")
	}
	io.Printfln(strings.Join(values, " "), a...)
}

// Print calls Fprint to the writer
func (io *Io) Print(a interface{}) {
	fmt.Fprint(io.writer, a)
}

// Printf calls Fprintf to the writer
func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

// Printfln calls Fprint to the writer
func (io *Io) Printfln(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format+"\n", a...)
}

// PrintInts prints ints with space and new line at the end
func (io *Io) PrintInts(ints []int) {
	for i, e := range ints {
		io.Print(e)

		if i == len(ints)-1 {
			io.Println()
		} else {
			io.Print(" ")
		}
	}
}

// Debug calls Println and Flush immediately
func (io *Io) Debug(a ...interface{}) {
	if io == nil {
		return
	}

	io.Println(a...)
	io.Flush()
}

// Assert checks the value equality for debug
func (io *Io) Assert(a, b interface{}) {
	if io == nil {
		return
	}

	if !reflect.DeepEqual(a, b) {
		_, _, line, _ := runtime.Caller(1)
		io.Debug("Diff:", line, "\na:", a, "\nb:", b)
	}
}

/* Math Helpers */

// MOD is 10^9 + 7
const MOD = 1000000007

// Max of the ints
func Max(numbers ...int) int {
	max := numbers[0]
	for i, number := range numbers {
		if i == 0 {
			continue
		}
		if number > max {
			max = number
		}
	}
	return max
}

// Min of the ints
func Min(numbers ...int) int {
	min := numbers[0]
	for i, number := range numbers {
		if i == 0 {
			continue
		}
		if min > number {
			min = number
		}
	}
	return min
}

// Sum of the ints
func Sum(numbers ...int) int {
	sum := 0

	for _, number := range numbers {
		sum += number
	}

	return sum
}

// Pow calculates the pow for int with O(log e)
func Pow(a, e int) int {
	if a < 0 || e < 0 {
		panic(fmt.Sprintf("Pow was called for a < 0 or e < 0, a: %d, e: %d", a, e))
	}

	if e == 0 {
		return 1
	}

	if e%2 == 0 {
		half := Pow(a, e/2)
		return half * half
	}

	return a * Pow(a, e-1)
}

// Abs returns the absolute value of the input
func Abs(a int) int {
	if a < 0 {
		return -a
	}

	return a
}

/* Structure Helpers */

// Set is orderless List
type Set map[interface{}]struct{}

// NewSet returns empty Set
func NewSet() *Set {
	return &Set{}
}

// Add the value to the set
func (set *Set) Add(value interface{}) {
	(*set)[value] = struct{}{}
}

// Includes check the set has the value
func (set *Set) Includes(value interface{}) bool {
	_, included := (*set)[value]
	return included
}

// Remove deletes the value from the set if exists
func (set *Set) Remove(value interface{}) {
	if !set.Includes(value) {
		return
	}

	delete(*set, value)
}

// ImmutableSort returns sorted slice without mutating original one
func ImmutableSort(slice []int) []int {
	res := make([]int, len(slice))
	copy(res, slice)
	sort.Ints(res)
	return res
}

/* Util helpers */

// Ternary is like `cond ? a : b`. should assert the returned value like `Ternary(cond, a, b).(int)`
func Ternary(cond bool, a, b interface{}) interface{} {
	if cond {
		return a
	}

	return b
}

// TernaryInt uses Ternary and assert the value as int
func TernaryInt(cond bool, a, b int) int {
	return Ternary(cond, a, b).(int)
}

// TernaryString uses Ternary and assert the value as string
func TernaryString(cond bool, a, b string) string {
	return Ternary(cond, a, b).(string)
}


Measured memory_bytes: 66816