#include <bits/stdc++.h>
using namespace std;
int n, m, ed, x, y;
int l[200005], qd[200005], qn[200005], p[200005];
void bd(int x, int y) { qd[++ed] = y, qn[ed] = l[x], l[x] = ed; }
int notinE(int x, int y) {
  for (int i = (l[x]); i; i = qn[i])
    if (qd[i] == y) return 0;
  return 1;
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = (0); i < (m); i++)
    scanf("%d%d", &x, &y), bd(x - 1, y - 1), bd(y - 1, x - 1);
  for (int i = (0); i < (n); i++) p[i] = i;
  for (int i = (0); i < (75); i++) {
    random_shuffle(p, p + n);
    p[n] = p[0];
    int ok = 1;
    for (int j = (1); j <= (m); j++)
      if (!notinE(p[j - 1], p[j])) {
        ok = 0;
        break;
      }
    if (ok) {
      for (int j = (1); j <= (m); j++)
        printf("%d %d\n", p[j - 1] + 1, p[j] + 1);
      return 0;
    }
  }
  puts("-1");
  return 0;
}
