#include<iostream>
#include<bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rep_r(i, n) for(int i = n-1; i >= 0; i--)
#define rep1(i, n) for(int i = 1; i <= (int)(n); i++)
#define REP(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((ll)(x).size())
#define bit(n) (1LL<<(n))
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

#define INF bit(60)
#define pb push_back
#define mod 1000000007

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

using namespace std;
using uif=uint_fast64_t;
using ll=long long int;
using tTree=__gnu_pbds::tree< ll , __gnu_pbds::null_type, less< ll >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>;

int qp(int a,ll b){int ans=1;do{if(b&1)ans=1ll*ans*a%mod;a=1ll*a*a%mod;}while(b>>=1);return ans;}
int qp(int a,ll b,int mo){int ans=1;do{if(b&1)ans=1ll*ans*a%mo;a=1ll*a*a%mo;}while(b>>=1);return ans;}

int gcd(int a,int b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};


#define FACSIZE 2002

ll invfac[FACSIZE];
ll fac[FACSIZE];

ll mod_pow(ll ,ll );
ll mod_add(ll ,ll );
ll mod_mul(ll ,ll );
ll mod_div(ll ,ll );
void make_fact(ll );
void make_invfact(ll );

struct graph{

  //ll rest;
  //vector<graph*> next;
  unordered_set<ll> next;
  vector<ll> in;
  vector<ll> out;
  //vector<graph*> in;
  //vector<graph*> out;
  //graph() : rest(0) {};
};

int main(void){

  ll n,m;
  cin>>n>>m;
  vector<ll> a(m);
  vector<ll> b(m);
  rep(i,m) cin>>a[i]>>b[i];

  if(m%2==1){
    cout << -1 << endl;
    return 0;
  }
  vector<graph> G(n+1);
  rep(i,m){
    ll A=a[i],B=b[i];
    G[A].next.insert(B);
    //G[A].rest++;
    G[B].next.insert(A);
    //G[B].rest++;
  }
  using pa=pair<ll,ll>;
  priority_queue<pa,vector<pa>,greater<pa>> pque;
  rep1(i,n){
    pque.push( make_pair( G[i].next.size() , -i ) );
  }

  while( !pque.empty() ){
    auto pq=pque.top();
    pque.pop();
    auto cur=-pq.second;
    //cout << pq.first << " " << pq.second << endl;
    if( G[cur].next.size() != pq.first ) continue;

    if( pq.first==1 ){
      ll nex=*begin( G[cur].next );
      ll outsize=G[ cur ].out.size();
      if(outsize%2==0){
        G[ cur ].in.push_back(nex);
        G[nex].out.push_back(cur);
      }
      else{
        G[ cur ].out.push_back(nex);
        G[nex].in.push_back(cur);
      }
      
      G[ cur ].next.erase(nex);
      G[nex].next.erase(cur);

      if(  G[nex].next.size()>0 ) pque.push( make_pair(G[nex].next.size(),-nex) );
    }
    else{
      ll nex=*(begin(G[cur].next));
      G[ cur ].out.push_back(nex);
      G[nex].in.push_back(cur);
      G[ cur ].next.erase(nex);
      G[nex].next.erase(cur);
      if(  G[nex].next.size()>0 ) pque.push( make_pair(G[nex].next.size(),-nex) );
      if(  G[cur].next.size()>0 ) pque.push( make_pair(G[cur].next.size(),-cur) );

    }

  }

  rep1(i,n){
    for(auto x:G[i].out){
      cout << i << " " << x << endl;
    }
  }

  return 0;

}

ll mod_pow(ll x,ll r){
  if(r==0) return 1;
  else if(r==1) return x%mod;
  else if(r%2==0){
    ll t=mod_pow(x,r/2)%mod;
    return t*t %mod;
  } 
  else{
    ll t=mod_pow(x,r/2)%mod;
    ll k= t*t %mod;
    return k*x%mod;
  } 
}
ll mod_add(ll a,ll b){
  return (a+b)%mod;
}

ll mod_mul(ll a,ll b){
  return (a*b)%mod;
}

ll mod_div(ll a,ll b){
  return mod_mul(a,mod_pow(b,mod-2));
}

void make_fact(ll n){
  fac[0]=1;
  rep(i,n){
    fac[i+1]=mod_mul(fac[i],i+1);
  }  
}

void make_invfact(ll n){
  invfac[n]= mod_pow( fac[n] ,mod-2);
  for(int i=n-1;i>=0;i--){
    invfac[i]=mod_mul(invfac[i+1],i+1);
  }

}

Measured memory_bytes: 25712