#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, n, m;
  vector<int> adj[111111];
  cin >> n >> m;
  for (int i = 0; i < m; ++i) {
    cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  vector<int> v(n, 0);
  for (int i = 0; i < n; ++i) {
    v[i] = i + 1;
  }
  vector<int> good(n + 1, 0);
  int i;
  for (i = 0; i < 100; ++i) {
    random_shuffle(v.begin(), v.end());
    int t = 0;
    for (int j = 0; j < n; ++j) {
      good[j] = 1;
      for (int k = 0; k < adj[v[j]].size(); ++k) {
        if (adj[v[j]][k] == v[(j + 1) % n]) good[j] = 0;
      }
      if (good[j]) t++;
      if (t == m) break;
    }
    if (t == m) break;
  }
  if (i == 100) {
    cout << -1 << endl;
    return 0;
  }
  int t = 0;
  for (int i = 0; i < n; ++i) {
    if (good[i]) {
      t++;
      cout << v[i] << " " << v[(i + 1) % n] << endl;
      if (t == m) break;
    }
  }
  return 0;
}
