#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T> using treap = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define int long long
#define REP(i, n) for (long long i = 0, max_i = (n); i < max_i; i++)
#define REPI(i, a, b) for (long long i = (a), max_i = (b); i < max_i; i++)
#define ALL(obj) begin(obj), end(obj)
#define RALL(obj) rbegin(obj), rend(obj)
#define fi first
#define se second
using ii = pair<int, int>;
vector<ii> dirs = {
  {1, 0}, {0, 1}, {-1, 0}, {0, -1},  // 4方向
  {1, 1}, {-1, 1}, {-1, -1}, {1, -1},  // 斜め
  {0, 0},  // 自身
};
template <class T> inline bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } return false; }
template <class T> inline bool chmin(T& a, const T& b) { if (a > b) { a = b; return true; } return false; }
template <class T, class S> vector<T> make_vec(size_t n, S x) { return vector<T>(n, x); }
template <class T, class... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec<T>(ts...))>(n, make_vec<T>(ts...)); }

// debug
template <class T> ostream& operator<<(ostream& s, vector<T>& d) { REP (i, d.size()) s << d[i] << (i == d.size() - 1 ? "" : " "); return s; }
template <class T> ostream& operator<<(ostream& s, vector<vector<T>>& d) { REP (i, d.size()) s << d[i] << (i == d.size() - 1 ? "" : "\n"); return s; }
template <class T, class S> ostream& operator<<(ostream& s, pair<T, S>& p) { s << "{" << p.first << ", " << p.second << "}"; return s; }
template <class T, class S> ostream& operator<<(ostream& s, map<T, S> m) { for (auto it = m.begin(); it != m.end(); it++) { s << *it << (next(it) == m.end() ? "" : "\n"); } return s; }
template <class T, class S> ostream& operator<<(ostream& s, unordered_map<T, S> m) { for (auto it = m.begin(); it != m.end(); it++) { s << *it << (next(it) == m.end() ? "" : "\n"); } return s; }
#ifdef _MY_DEBUG
  #define dump(...) cerr << "/* " << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << endl, dump_func(__VA_ARGS__), cerr << "*/\n\n";
#else
  #define dump(...)
  #define endl "\n"
#endif
void dump_func() { cerr << endl; }
template <class Head, class... Tail> void dump_func(Head&& h, Tail&&... t) { cerr << h << (sizeof...(Tail) == 0 ? "" : ", "), dump_func(forward<Tail>(t)...); }

struct Fast { Fast() { cin.tie(0); ios::sync_with_stdio(false); } } fast;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
constexpr int MOD = 1000000007;
// *************** TEMPLATE END *************** 

struct UnionFind {
  int cnt; // 集合の数
  vector<int> number; // 0以上のとき親のindex, 負のときは集合サイズ
  vector<int> data1, data2; // 連結成分ごとのデータ
  UnionFind(int n) : cnt(n), number(n, -1) {}
  UnionFind(const vector<int>& data1, const vector<int>& data2) :
    cnt(data1.size()), number(data1.size(), -1), data1(data1), data2(data2) {}
  int root(int x) {
    return number[x] < 0 ? x : number[x] = root(number[x]);
  }
  void unite(int x, int y) {
    x = root(x); y = root(y);
    if (x == y) return;
    if (number[y] < number[x]) swap(x, y);
    // yをxにマージ
    number[x] += number[y];
    number[y] = x;
    // // dataのマージ方法に合わせて変える
    // data1[x] += data1[y];
    // data2[x] += data2[y];
    cnt--;
  }
  bool is_same(int x, int y) { return root(x) == root(y); }
  int size(int x) { return -number[root(x)]; }
  int& ref1(int x) { return data1[root(x)]; }
  int& ref2(int x) { return data2[root(x)]; }
};

signed main() {
  int n, m; cin >> n >> m;
  vector<vector<int>> g(n);
  UnionFind uf(n);
  vector<ii> ans;
  vector<int> parity(n);
  REP (i, m) {
    int u, v; cin >> u >> v;
    u--; v--;
    if (uf.is_same(u, v)) {
      ans.push_back({u, v});
      parity[u] = !parity[u];
    } else {
      uf.unite(u, v);
      g[u].push_back(v);
      g[v].push_back(u);
    }
  }
  assert(uf.cnt == 1);
  if (m % 2) {
    cout << -1 << endl;
    return 0;
  }
  function<void(int, int)> dfs = [&](int v, int prev) {
    for (int s : g[v]) if (s != prev) {
      dfs(s, v);
    }
    if (prev == -1) return;
    if (parity[v]) {
      ans.push_back({v, prev});
      parity[v] = !parity[v];
    } else {
      ans.push_back({prev, v});
      parity[prev] = !parity[prev];
    }
  };
  dfs(0, -1);
  assert(ans.size() == m);
  REP (i, n) assert(parity[i] == 0);
  for (auto& p : ans) cout << p.fi + 1 << " " << p.se + 1 << endl;
}


Measured memory_bytes: 16752