#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10, INF = 0x3f3f3f3f;
const long long mod = 998244353, LINF = 0x3f3f3f3f3f3f3f3f;
;
const double eps = 1e-10, Pi = 2 * acos(0);
int n, m;
int a[N];
map<pair<int, int>, int> mp;
void solve() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    mp[make_pair(u, v)] = 1;
    mp[make_pair(v, u)] = 1;
  }
  for (int i = 1; i <= n; i++) a[i] = i;
  int t = 500, flag = 0;
  while (t--) {
    random_shuffle(a + 1, a + 1 + n);
    int cnt = 0;
    for (int i = 1; i <= n; i++) {
      int u = a[i], v = a[i % n + 1];
      if (!mp[make_pair(u, v)]) cnt++;
    }
    if (cnt >= m) {
      flag = 1;
      break;
    }
  }
  if (flag == 0)
    printf("-1\n");
  else {
    int cnt = 0;
    for (int i = 1; i <= n; i++) {
      int u = a[i], v = a[i % n + 1];
      if (!mp[make_pair(u, v)]) {
        printf("%d %d\n", u, v);
        cnt++;
      }
      if (cnt == m) break;
    }
  }
}
int main() {
  int ce, c = 1, flag = 1;
  solve();
  return 0;
}
