#include "bits/stdc++.h"
#define YES "YES"
#define Yes "Yes"
#define NO "NO"
#define No "No"
#pragma GCC optimize ("O3")
#define YESNO OUT(three(solve(),YES,NO))
#define YesNo OUT(three(solve(),Yes,No))
#define ECHO OUT(solve())
#define three(A,B,C) ((A)?(B):(C))
#define FOR(i,a,b)  for(LL i=(a);i< (LL)(b);i++)
#define EFOR(i,a,b) for(LL i=(a);i<=(LL)(b);i++)
#define RFOR(i,a,b) for(LL i=(a);i>=(LL)(b);i--)
#define REP(i,b) FOR(i,zero,b)

#define EREP(i,b) EFOR(i,zero,b)
#define RREP(i,b) RFOR(i,b-1,zero)
#define ALL(c) c.begin(),c.end()
#define MAX(c) (*max_element(ALL(c)))
#define MIN(c) (*min_element(ALL(c)))
#define MP make_pair
#define FI first
#define SE second
#define SI(x) (LL(x.size()))
#define PB emplace_back
#define DEBUG(a) OUT(a)
#define DEBUG2(a,b) OUT2(a,b)

#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define reps FOR
#define rreps(i,a,b) for (int i=int(b)-1;i>=(a);--i)
#define rrep(i,b) rreps(i,0,b)

#define cat cout << __LINE__ << endl
#define OUT(a) cout << (a) << endl
#define OUT2(a,b) cout << (a) <<" "<<(b) << endl
#define int long long
#define zero 0LL
#define pb PB
using namespace std;
template<typename T> inline bool middle(T a, T b, T c) { return b <= a && a <= c; }
template<class T> inline bool MX(T &l, const T &r) { return l < r ? l = r, 1 : 0; }
template<class T> inline bool MN(T &l, const T &r) { return l > r ? l = r, 1 : 0; }
typedef long long LL;
typedef long double ld;
typedef LL ut;
typedef vector<ut> VI;
typedef vector<VI> VII;
typedef pair<ld, ut> pld;
typedef vector<pld> Vpld;
typedef pair<ut, ut> pr;
typedef pair<ut, pr> ppr;
typedef vector<pr> Vpr;
typedef vector<ppr> Vppr;
typedef priority_queue<pr, Vpr, greater<pr> > PQ;
const LL MOD=1e9+7;
#define UNIQUE(X) (X).erase(unique(all(X)),(X).end())
inline void outputVI(VI x) { REP(i, SI(x)) { cout << three(i, " ", "") << x[i]; }OUT(""); }
int dx[] = { 0,1,0,-1,1,1,-1,-1,0 }, dy[] = { 1,0,-1,0,1,-1,1,-1,0 };const int SIZE1 = 5e5 + 1000;
const int SIZE2 = 2010;
const int SIZE3 = 188;
const int SIZE = SIZE1;
const LL p = 7 + 1e9;
const LL INF = 1LL << 60;
const long double EPS = 1e-7;
class UnionFind{
 
  vector<int> unions,talls,sents,dists,sizes;
  int size;
public:
  UnionFind(){}
  UnionFind(int size):size(size){
    init();
  }
  void init(){
    unions=vector<int>(size);
    talls=vector<int>(size);
    sents=vector<int>(size);
    dists=vector<int>(size);
    sizes=vector<int>(size);
    FOR(i,0,size){
      unions[i]=i;
      sents[i]=0;
      sizes[i]=1;
//      ns[i].PB(pr(0,1));
      talls[i]=1;
    }
  }
  int find(int x,int t=0){
    if(unions[x]==x || sents[x]>t) return x;
    return find(unions[x],t);
 
  }
  int minisize(int x){
    if(x==unions[x]) return sizes[x];
    return minisize(find(x));
  }
  bool isFriend(int a,int b,int t=0){
    return find(a,t)==find(b,t);  
  }
  void unite(int a,int b,int t=0){
    if(isFriend(a,b,t)) return;
    a=find(a,t);
    b=find(b,t);
    if(talls[a]<talls[b]) unite(b,a,t);
    else{
      sizes[a]+=sizes[b];
      sents[b]=t;
      talls[a]=max(talls[a],talls[b]+1);
      unions[b]=a;
      dists[b]=1;
//      ns[a].PB(pr(t,ns[b].back().second+ns[a].back().second));
    }
  }
};
ut N, M, K,  H, W, Q, D, T,X;
//ut N,A,B,C,D,E,F,G,H,I,J,O,P,Q,R,T,U;
VI edges[SIZE];

LL A[SIZE];
LL dfs(int now,int from=-1){
  for(auto next:edges[now]){
    if(next==from) continue;
    if(dfs(next,now)){
      cout << now << " " << next << endl;
      A[now]++;
    }
  }
  if(A[now]%2){
    cout << now << " " << from << endl;
    return 0;
  }
  return 1;
}
LL solve(){

  cin >> N >> M;
  UnionFind uf(N+1);
  if(M%2) {
    cout << -1 << endl;
    return 0;
  }
  REP(i,M){
    LL a,b;
    cin >> a>> b;
    if(uf.isFriend(a,b)){
       cout << a << " "<< b << endl;
       A[a]++;
       continue; 
    }
    uf.unite(a,b);
    edges[a].pb(b);
    edges[b].pb(a);
  }
  dfs(1);
  return 0;
}

signed main()
{
  ios_base::sync_with_stdio(false);
  cout<<fixed<<setprecision(0);
  solve();
}



Measured memory_bytes: 28160