#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 7;
const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, -1, 1};
int n, m;
vector<int> v[100001];
int a[100001];
inline int edge(int x, int y) {
  for (int i = 0; i < v[x].size(); i++)
    if (v[x][i] == y) return 1;
  return 0;
}
int check() {
  int ret = 1;
  for (int i = 0; i < m; i++)
    if (edge(a[i], a[i + 1])) {
      ret = 0;
      swap(a[i], a[rand() % n]);
      a[n] = a[0];
    }
  return ret;
}
int main() {
  cin.sync_with_stdio(false);
  cout.sync_with_stdio(false);
  srand((unsigned)time(NULL));
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    v[x].push_back(y);
    v[y].push_back(x);
  }
  for (int i = 1; i <= n; i++) a[i] = i;
  random_shuffle(a + 1, a + 1 + n);
  a[0] = a[n];
  bool flag = false;
  while (clock() < 2.8 * CLOCKS_PER_SEC) {
    if (check()) {
      flag = 1;
      break;
    }
  }
  if (flag) {
    for (int i = 0; i < m; i++) cout << a[i] << ' ' << a[i + 1] << endl;
  } else
    cout << -1 << endl;
  return 0;
}
