#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3f;
const double pi = 2 * acos(0.0);
const double eps = 1e-6;
const long long mod = 998244353;
const int N = 1e5 + 10;
const int M = 1e5 + 10;
map<pair<int, int>, int> mp;
int a[N], ans[N];
int main() {
  int n, m;
  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++) {
    mp[make_pair(i, i)] = 1;
    a[i] = i;
  }
  int fuck = 500, cnt;
  while (fuck--) {
    cnt = 0;
    random_shuffle(a + 1, a + n + 1);
    a[0] = a[n];
    for (int i = 1; i <= n; i++) {
      int u = a[i - 1], v = a[i];
      if (!mp[make_pair(u, v)]) ans[cnt++] = i;
      if (cnt >= m) break;
    }
    if (cnt < m) continue;
    for (int i = 0; i < cnt; i++) {
      printf("%d %d\n", a[ans[i] - 1], a[ans[i]]);
    }
    return 0;
  }
  puts("-1");
  return 0;
}
