#include<bits/stdc++.h>
using namespace std;
int gi() {
	char ch='!'; int res=0, f=0;
	while(ch<'0' || ch>'9') { ch=getchar(); if(ch == '-') f=1; }
	while(ch>='0' && ch<='9') res=res*10+ch-'0', ch=getchar();
	return f?-res:res;
}
const int N=1e5+100;
int n,m,fa[N],deg[N],head[N],ce;
struct edge { int to,nxt; } e[N<<1];
void lnk(int a,int b) { e[++ce]=(edge){b,head[a]}, head[a]=ce; }
int getfa(int x) { return x == fa[x]?x:fa[x]=getfa(fa[x]); }
void dfs(int u,int lst) {
	for(int i=head[u];i;i=e[i].nxt) {
		int v=e[i].to;
		if(v == lst) continue;
		dfs(v,u);
	}
	if(!lst) return;
	if(deg[u]&1)
		++deg[u], printf("%d %d\n",u,lst);
	else
		++deg[lst], printf("%d %d\n",lst,u);
}
int main() {
	n=gi(), m=gi();
	if(m&1) { puts("-1"); return 0; }
	for(int i=1;i<=n;++i) fa[i]=i;
	for(int i=1,u,v,fu,fv;i<=m;++i) {
		u=gi(), v=gi(), fu=getfa(u), fv=getfa(v);
		if(fu == fv) { printf("%d %d\n",u,v); ++deg[u]; continue; }
		fa[fu]=fv, lnk(u,v), lnk(v,u);
	}
	dfs(1,0);
	return 0;
}