#include <bits/stdc++.h>
using namespace std;
int a[100009][2];
int P[100009];
int main() {
  int n, m;
  cin >> n >> m;
  int x, y;
  for (int(i) = (0); i < (m); ++(i)) {
    scanf("%d%d", &x, &y);
    if (a[x][0])
      a[x][1] = y;
    else
      a[x][0] = y;
    if (a[y][0])
      a[y][1] = x;
    else
      a[y][0] = x;
  }
  for (int(i) = (0); i < (n); ++(i)) P[i] = i;
  for (int(iter) = (0); iter < (7777777); ++(iter)) {
    random_shuffle(P, P + n);
    bool ok = true;
    for (int(i) = (0); i < (min(m, n - 1)); ++(i)) {
      int p1 = P[i] + 1, p2 = P[i + 1] + 1;
      if (a[p1][0] == p2 || a[p1][1] == p2) {
        ok = 0;
        break;
      }
    }
    if (m == n && a[P[0] + 1][0] == P[n - 1] + 1 ||
        a[P[0] + 1][1] == P[n - 1] + 1)
      ok = false;
    if (ok) {
      for (int(i) = (0); i < (min(m, n - 1)); ++(i))
        printf("%d %d\n", P[i] + 1, P[i + 1] + 1);
      if (m == n) printf("%d %d\n", P[0] + 1, P[n - 1] + 1);
      return 0;
    }
  }
  cout << -1;
  return 0;
}
