#include <bits/stdc++.h>
using namespace std;
const int MaxN = 200005;
vector<int> a[MaxN];
int p[MaxN];
int main() {
  clock_t start_time = clock();
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) a[i].clear();
  for (int i = 1; i <= m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    a[u].push_back(v);
    a[v].push_back(u);
  }
  for (int i = 1; i <= n; i++) p[i] = i;
  p[n + 1] = 0;
  while (((float)(clock() - start_time)) / CLOCKS_PER_SEC < 2.7) {
    random_shuffle(p + 1, p + n + 1);
    int good = true;
    for (int i = 1; i <= m; i++)
      for (__typeof((a[p[i]]).begin()) pp = (a[p[i]]).begin();
           pp != (a[p[i]]).end(); pp++)
        if (*pp == p[i + 1]) good = false;
    if (n == m)
      for (__typeof((a[p[n]]).begin()) pp = (a[p[n]]).begin();
           pp != (a[p[n]]).end(); pp++)
        if (*pp == p[1]) good = false;
    if (good) {
      for (int i = 1; i <= m; i++)
        if (i != n) printf("%d %d\n", p[i], p[i + 1]);
      if (n == m) printf("%d %d\n", p[1], p[n]);
      return 0;
    }
  }
  printf("-1\n");
  return 0;
}
