using System;
using System.Collections.Generic;
using System.Text;

public class Program
{
    private int N, M;
    private List<int>[] Edge;
    private bool[] Cnt;
    private StringBuilder Sb;
    private bool[] B;

    public void Solve()
    {
        var sc = new Scanner();
        N = sc.NextInt();
        M = sc.NextInt();
        if (M % 2 == 1)
        {
            Console.WriteLine(-1);
            return;
        }

        Edge = new List<int>[N];
        Cnt = new bool[N];

        for (int i = 0; i < N; i++)
        {
            Edge[i] = new List<int>();
        }

        for (int i = 0; i < M; i++)
        {
            int a = sc.NextInt() - 1;
            int b = sc.NextInt() - 1;
            Edge[a].Add(b);
            Edge[b].Add(a);
        }
        B = new bool[N];
        Sb = new StringBuilder();
        Search(0, -1);
        Console.Write(Sb.ToString());
    }

    
    private void Search(int i, int parent)
    {
        B[i] = true;
        foreach (var j in Edge[i])
        {
            if (B[j])
            {
                if (j != parent && i < j)
                {
                    Cnt[i] = !Cnt[i];
                    Sb.AppendLine($"{i + 1} {j + 1}");
                }
            }
            else
            {
                Search(j, i);
            }
        }

        if (parent != -1)
        {
            if (Cnt[i])
            {
                Sb.AppendLine($"{i + 1} {parent + 1}");
                Cnt[i] = false;
            }
            else
            {
                Sb.AppendLine($"{parent + 1} {i + 1}");
                Cnt[parent] = !Cnt[parent];
            }
        }
    }


    public static void Main(string[] args)
    {
        new Program().Solve();
    }
}

class Scanner
{
    public Scanner()
    {
        _pos = 0;
        _line = new string[0];
    }

    const char Separator = ' ';
    private int _pos;
    private string[] _line;

    #region スペース区切りで取得

    public string Next()
    {
        if (_pos >= _line.Length)
        {
            _line = Console.ReadLine().Split(Separator);
            _pos = 0;
        }

        return _line[_pos++];
    }

    public int NextInt()
    {
        return int.Parse(Next());
    }

    public long NextLong()
    {
        return long.Parse(Next());
    }

    public double NextDouble()
    {
        return double.Parse(Next());
    }

    #endregion

    #region 型変換

    private int[] ToIntArray(string[] array)
    {
        var result = new int[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = int.Parse(array[i]);
        }

        return result;
    }

    private long[] ToLongArray(string[] array)
    {
        var result = new long[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = long.Parse(array[i]);
        }

        return result;
    }

    private double[] ToDoubleArray(string[] array)
    {
        var result = new double[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = double.Parse(array[i]);
        }

        return result;
    }

    #endregion

    #region 配列取得

    public string[] Array()
    {
        if (_pos >= _line.Length)
            _line = Console.ReadLine().Split(Separator);

        _pos = _line.Length;
        return _line;
    }

    public int[] IntArray()
    {
        return ToIntArray(Array());
    }

    public long[] LongArray()
    {
        return ToLongArray(Array());
    }

    public double[] DoubleArray()
    {
        return ToDoubleArray(Array());
    }

    #endregion
}

Measured memory_bytes: 49020