import std.stdio, std.conv, std.functional, std.string;
import std.algorithm, std.array, std.container, std.range, std.typecons;
import std.numeric, std.math, std.random;
import core.bitop;

string FMT_F = "%.10f";

static string[] s_rd;
T RD(T = long)() { while(!s_rd.length) s_rd = readln.chomp.split; string res = s_rd[0]; s_rd.popFront; return res.to!T; }
string RDR()() { return readln.chomp; }
T[] ARR(T = long)(in string str, T fix = 0) { auto r = str.split.to!(T[]); r[] += fix; return r; }
T[] RDA(T = long)(T fix = 0) { auto r = readln.chomp.split.to!(T[]); r[] += fix; return r; }
T[][] RDA2(T = long)(size_t n, T[] fix = []) { auto r = new T[][](n); foreach (i; 0..n) { r[i] = readln.chomp.split.to!(T[]); foreach (j, e; fix) r[i][j] += e; } return r; }
size_t[] MAKE_IDX(alias less = "a < b", Range)(Range range) { auto idx = new size_t[](range.length); makeIndex!(less)(range, idx); return idx;}
size_t MIN_POS(alias less = "a < b", Range)(Range range) { auto r = minPos!(less)(range); return range.length - r.length; }

bool inside(T)(T x, T b, T e) { return x >= b && x < e; }
long lcm(long x, long y) { return x * y / gcd(x, y); }

long mod = 10^^9 + 7;
//long mod = 998244353;
//long mod = 1_000_003;
void moda(ref long x, long y) { x = (x + y) % mod; }
void mods(ref long x, long y) { x = ((x + mod) - (y % mod)) % mod; }
void modm(ref long x, long y) { x = (x * y) % mod; }

void main()
{
	auto N = RD;
	auto M = RD;
	auto edges = new bool[long][](N);
	foreach (i; 0..M)
	{
		auto A = RD-1;
		auto B = RD-1;
		edges[A][B] = true;
		edges[B][A] = true;
	}

	if (M % 2 == 1)
		writeln(-1);
	else
	{
		long[2][] ans;
		long cnt2;
		
		long[3][] open = [[0, 0, 0]];
		auto close = new bool[](N);
		close[0] = true;
		while (!open.empty)
		{
			++cnt2;
			if (cnt2 == N) break;
			auto n    = open.front; open.popFront;
			auto from = n[0];
			auto c    = edges[from].keys.length;
			auto cnt  = n[1];
			auto p    = n[2];
			foreach (key; edges[from].keys)
			{
				auto to = key;
				if (to == p) continue;
				auto c2 = edges[to].keys.length;
				if ((c + cnt) % 2 == 1/* && c2 % 2 == 1*/)
				{
					ans ~= [to, from];
					--c;
					if (!close[to])
						open ~= [to, 0, from];
				}
				else
				{
					ans ~= [from, to];
					--c;
					++cnt;
					if (!close[to])
						open ~= [to, -1, from];
				}
				close[to] = true;
			}
		}

		foreach (e; ans)
		{
			writeln(e[0]+1, " ", e[1]+1);
		}
	}
	
	stdout.flush();
	debug readln();
}