# pragma GCC optimize ("O3")
# pragma GCC optimize ("Ofast")
# pragma GCC optimize ("unroll-loops")
# pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

typedef unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef tuple<int, int, int> ti3;
typedef tuple<int, int, int, int> ti4;
typedef stack<int> si;
typedef queue<int> qi;
typedef priority_queue<int> pqi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;
typedef tuple<ll, ll, ll> tl3;
typedef tuple<ll, ll, ll, ll> tl4;
typedef stack<ll> sl;
typedef queue<ll> ql;
typedef priority_queue<ll> pql;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>ordered_set;

const int dx[4] = { 1,0,-1,0 };
const int dy[4] = { 0,1,0,-1 };
const int ddx[8] = { 0,0,1,1,1,-1,-1,-1 }, ddy[8] = { 1,-1,1,0,-1,1,0,-1 };
ll POW(ll a, ll b, ll MMM) { ll ret = 1; for (; b; b >>= 1, a = (a*a) % MMM)if (b & 1)ret = (ret*a) % MMM; return ret; }
ll GCD(ll a, ll b) { return b ? GCD(b, a%b) : a; }
ll LCM(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a / GCD(a, b) * b; }
ll INV(ll a, ll m) {
  ll m0 = m, y = 0, x = 1;
  if (m == 1)	return 0;
  while (a > 1) {
    ll q = a / m;
    ll t = m;
    m = a % m, a = t;
    t = y;
    y = x - q * y;
    x = t;
  }
  if (x < 0) x += m0;
  return x;
}
pll EXGCD(ll a, ll b) {
  if (b == 0) return { 1,0 };
  auto t = EXGCD(b, a%b);
  return { t.second,t.first - t.second*(a / b) };
}
bool OOB(ll x, ll y, ll N, ll M) { return 0 > x || x >= N || 0 > y || y >= M; }
#define X first
#define Y second
#define rep(i,a,b) for(int i = a; i < b; i++)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(a) ((int)(a.size()))
#define sf1(a) cin >> a
#define sf2(a,b) cin >> a >> b
#define sf3(a,b,c) cin >> a >> b >> c
#define sf4(a,b,c,d) cin >> a >> b >> c >> d
#define sf5(a,b,c,d,e) cin >> a >> b >> c >> d >> e
#define sf6(a,b,c,d,e,f) cin >> a >> b >> c >> d >> e >> f
#define pf1(a) cout << (a) << ' '
#define pf2(a,b) cout << (a) << ' ' << (b) << ' '
#define pf3(a,b,c) cout << (a) << ' ' << (b) << ' '<< (c) << ' '
#define pf4(a,b,c,d) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '
#define pf5(a,b,c,d,e) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << ' '
#define pf6(a,b,c,d,e,f) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << ' ' << (f) << ' '
#define pf0l() cout << '\n';
#define pf1l(a) cout << (a) << '\n'
#define pf2l(a,b) cout << (a) << ' ' << (b) << '\n'
#define pf3l(a,b,c) cout << (a) << ' ' << (b) << ' '<< (c) << '\n'
#define pf4l(a,b,c,d) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << '\n'
#define pf5l(a,b,c,d,e) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << '\n'
#define pf6l(a,b,c,d,e,f) cout << (a) << ' ' << (b) << ' '<< (c) << ' '<< (d) << ' '<< (e) << ' ' << (f) << '\n'
#define pfvec(V) for(auto const &t : V) pf1(t)
#define pfvecl(V) for(auto const &t : V) pf1(t); pf0l()



int n,m;
int cnt[100004];
vi adj[100004];
bool vis[100004];
vector<pii> ans;
vi adj_tree[100004];
void dfs1(int cur, int r){
    //cout << "dfs1 " << cur << ' ' << r << '\n';
  for(auto nxt : adj[cur]){
    if(nxt==r) continue;
    if(vis[nxt]){
      if(cur<nxt){
        ans.pb({cur,nxt});
        cnt[cur]++;
      }
      continue;
    }
    vis[nxt] = 1;
    adj_tree[cur].pb(nxt);
    dfs1(nxt,cur);
  }
}

void dfs2(int cur, int r){
  //cout << "dfs2 " << cur << ' ' << r << '\n';
  for(auto nxt : adj_tree[cur]){
    if(nxt==r) continue;
    dfs2(nxt,cur);
  }
  if(cur==1) return;
  if(cnt[cur]%2 == 0){
    ans.pb({r,cur});
    cnt[r]++;
  }
  else{
    ans.pb({cur,r});
    cnt[cur]++;
  }
}

int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed;
  cout.precision(20);
///////////////////////////////////////////////
  sf2(n,m);
  rep(i,0,m){
    int a,b;
    sf2(a,b);
    adj[a].pb(b);
    adj[b].pb(a);
  }
  if(m%2==1){
    pf1l(-1);
    return 0;
  }
  vis[1]=1;
  dfs1(1,0);
  dfs2(1,0);
  for(auto e : ans){
    pf2l(e.X,e.Y);
  }  
  //rep(i,1,n+1) pf1(cnt[i]);

}

Measured memory_bytes: 24696