#include <bits/stdc++.h>
#ifdef LOCAL_DEBUG
#define DEBUG 1
#define CERR if(DEBUG) cerr
#define MACRO(_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,NAME,...) NAME
#define pr(...) CERR<<MACRO(__VA_ARGS__,pr10,pr9,pr8,pr7,pr6,pr5,pr4,pr3,pr2,pr1)(__VA_ARGS__)<<endl
#define pr1(a) (#a)<<"="<<(a)<<" "
#define pr2(a,b) pr1(a)<<pr1(b)
#define pr3(a,b,c) pr1(a)<<pr2(b,c)
#define pr4(a,b,c,d) pr1(a)<<pr3(b,c,d)
#define pr5(a,b,c,d,e) pr1(a)<<pr4(b,c,d,e)
#define pr6(a,b,c,d,e,f) pr1(a)<<pr5(b,c,d,e,f)
#define pr7(a,b,c,d,e,f,g) pr1(a)<<pr6(b,c,d,e,f,g)
#define pr8(a,b,c,d,e,f,g,h) pr1(a)<<pr7(b,c,d,e,f,g,h)
#define pr9(a,b,c,d,e,f,g,h,i) pr1(a)<<pr8(b,c,d,e,f,g,h,i)
#define pr10(a,b,c,d,e,f,g,h,i,j) pr1(a)<<pr9(b,c,d,e,f,g,h,i,j)
#define prArr(a){CERR<<(#a)<<"={";int i=0;for(auto t:(a))CERR<<(i++?", ":"")<<t;CERR<<"}"<<endl;}
#else
#define DEBUG 0
#define pr(...)
#define prArr(a)
#endif
using namespace std;
using Int = long long;
using _int = int;
using ll = long long;
using Double = long double;
const Int INF = (1LL<<60)+1e9; // ~ 1.15 * 1e18
const Int mod = (1e9)+7;
const Double EPS = 1e-8;
const Double PI = 6.0 * asin((Double)0.5);
using P = pair<Int,Int>;
template<class T> T Max(T &a,T b){return a=max(a,b);}
template<class T> T Min(T &a,T b){return a=min(a,b);}
template<class T1, class T2> ostream& operator<<(ostream& o,pair<T1,T2> p){return o<<"("<<p.first<<","<<p.second<<")";}
template<class T1, class T2, class T3> ostream& operator<<(ostream& o,tuple<T1,T2,T3> t){return o<<"("<<get<0>(t)<<","<<get<1>(t)<<","<<get<2>(t)<<")";}
template<class T1, class T2> istream& operator>>(istream& i,pair<T1,T2> &p){return i>>p.first>>p.second;}
template<class T> ostream& operator<<(ostream& o,vector<T> a){Int i=0;for(T t:a)o<<(i++?" ":"")<<t;return o;}
template<class T> istream& operator>>(istream& i,vector<T> &a){for(T &t:a)i>>t;return i;}
//INSERT ABOVE HERE

Int N;
vector<vector<Int> > G;
vector<set<Int> > T;


void makeTree(Int pos){
  static Int used[100010];
  used[pos] = 1;
  for(Int to:G[pos]){
    if(used[to]) continue;
    used[to] = 1;
    makeTree(to);
    T[pos].insert(to);
  }
}


set<P> ans;
vector<Int> indeg, outdeg;

void dfs(Int pos, Int pre){

  for(Int to:G[pos]){
    if(to == pre) continue;
    if(T[pos].count(to)) continue;
    if(ans.count(P(pos, to))) continue;
    if(ans.count(P(to, pos))) continue;
    ans.emplace(pos, to);
    outdeg[pos]++;
    indeg[to]++;
  }

  for(Int to:T[pos]){
    if(to == pre) continue;
    dfs(to, pos);
  }

  if(pre == -1) return;
  if(outdeg[pos] % 2 == 0) {
    ans.emplace(pre, pos);
    indeg[pos]++;
    outdeg[pre]++;
  }
  else {
    ans.emplace(pos, pre);
    outdeg[pos]++;
    indeg[pre]++;
  }
}



signed main(){
  srand((unsigned)time(NULL));
  cin.tie(0);
  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(12);

  Int M;
  cin>>N>>M;
  G.resize(N);
  T.resize(N);
  indeg.resize(N);
  outdeg.resize(N);
  for(Int i=0;i<M;i++){
    Int a, b;
    cin>>a>>b; a--, b--;
    G[a].push_back(b);
    G[b].push_back(a);
  }

  if(M % 2){
    cout<<-1<<endl;
    return 0;
  }

  makeTree(0);
  dfs(0, -1);

  for(auto p:ans) cout<<p.first + 1<<" "<<p.second + 1<<endl;

  vector<Int> in(N), out(N);
  for(auto p:ans) out[p.first]++, in[p.second]++;

  for(Int i=0;i<N;i++){
    assert(out[i]%2 == 0);
  }

  return 0;
}


Measured memory_bytes: 35840