//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using db = double;
using ld = long double;
template <typename T> using V = vector<T>;
template <typename T> using VV = vector<vector<T>>;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define siz(v) (ll)(v).size()
#define rep(i, a, n) for(ll i = a; i < (ll)(n); ++i)
#define repr(i, a, n) for(ll i = n - 1; (ll)a <= i; --i)
#define ENDL '\n'
typedef pair<int, int> Pi;
typedef pair<ll, ll> PL;
constexpr ll mod = 1000000007;  // 998244353;
constexpr ll INF = 1000000099;
constexpr ll LINF = (ll)(1e18 + 99);
const ld PI = acos((ld)-1);
const vector<ll> dx = {-1, 1, 0, 0}, dy = {0, 0, -1, 1};
template <typename T, typename U> inline bool chmin(T& t, const U& u) {
  if(t > u) {
    t = u;
    return 1;
  }
  return 0;
}
template <typename T, typename U> inline bool chmax(T& t, const U& u) {
  if(t < u) {
    t = u;
    return 1;
  }
  return 0;
}
template <typename T> inline T gcd(T a, T b) { return b ? gcd(b, a % b) : a; }

template <typename T, typename Y> inline T mpow(T a, Y n) {
  T res = 1;
  for(; n; n >>= 1) {
    if(n & 1) res = res * a;
    a = a * a;
  }
  return res;
}

template <typename T, typename Y>
ostream& operator<<(ostream& os, const pair<T, Y>& p) {
  return os << "{" << p.fs << "," << p.sc << "}";
}
template <typename T> ostream& operator<<(ostream& os, const V<T>& v) {
  os << "{";
  for(auto e : v) os << e << ",";
  return os << "}";
}
template <typename... Args> void debug(Args&... args) {
  for(auto const& x : {args...}) { cerr << x << ' '; }
  cerr << ENDL;
}

struct phash {
  inline size_t operator()(const PL& p) const {
    const auto h1 = hash<int>()(p.first);
    const auto h2 = hash<int>()(p.second);
    return h1 ^ (h2 << 1);
  }
};

VV<int> e;
V<ll> ou,ans(0);
V<bool> used;
set<Pi> se;


void dfs(int now,int pre) {
  for(auto&& to : e[now]) {
    if(to==pre)continue;
    
    if(used[to]){
      if(se.count({min(now,to),max(now,to)}))continue;
      ans.eb(now);
      ans.eb(to);
      ou[now]++;
      se.insert({min(now,to),max(now,to)});
    }else{
      used[to]=true;
      dfs(to,now);
    }
  }
  if(now==0){
    return ;
  }
  
  if(ou[now]%2){
    ans.eb(now);
    ans.eb(pre);
  }else{
    ans.eb(pre);
    ans.eb(now);
    ou[pre]++;
  }
  se.insert({min(now,pre),max(now,pre)});
}

signed main() {
  cin.tie(0);
  cerr.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(20);
  ll n, m;
  cin >> n >> m;
  e.assign(n, V<int>(0));
  ou.assign(n, 0);
  used.assign(n, false);

  rep(i, 0, m) {
    int a, b;
    cin >> a >> b;
    --a;
    --b;
    e[a].eb(b);
    e[b].eb(a);
  }

  if(m%2){
    cout<<-1<<ENDL;
    return 0;
  }

  used[0]=true;
  dfs(0,-1);

  rep(i, 0, siz(ans)) {
    cout << ans[i] + 1 << " " << ans[i + 1] + 1 << ENDL;
    ++i;
  }
}
//! ( . _ . ) !
// CHECK overflow,vector_size,what to output?

Measured memory_bytes: 23516