#include <bits/stdc++.h>
using namespace std;
int p[101000];
map<pair<int, int>, int> mp;
int main() {
  mp.clear();
  pair<int, int> p1;
  int x, y, n, m;
  scanf("%d%d", &n, &m);
  if (n == 1) {
    puts("");
    return 0;
  }
  for (int i = 0; i < n; ++i) {
    p[i] = i + 1;
  }
  for (int i = 0; i < m; ++i) {
    scanf("%d%d", &x, &y);
    if (x > y) swap(x, y);
    p1.first = x;
    p1.second = y;
    mp[p1] = 1;
  }
  int flag = 0;
  for (int ri = 0; ri <= 10000; ++ri) {
    for (int j = 1; j < n; ++j) {
      int x = rand() % (j + 1);
      swap(p[x], p[j]);
    }
    int cnt = 0;
    p[n] = p[0];
    for (int j = 1; j <= n; ++j) {
      int x, y;
      x = p[j - 1];
      y = p[j];
      if (x > y) swap(x, y);
      p1.first = x;
      p1.second = y;
      if (mp.find(p1) == mp.end()) {
        cnt++;
      }
    }
    if (cnt >= m) {
      flag = 1;
    }
    if (flag) break;
  }
  if (!flag)
    puts("-1");
  else {
    p[n] = p[0];
    int cnt = 0;
    for (int i = 0; i < n; i++) {
      int x, y;
      x = p[i];
      y = p[i + 1];
      if (x > y) swap(x, y);
      p1.first = x;
      p1.second = y;
      if (mp.find(p1) == mp.end()) {
        cnt++;
        printf("%d %d\n", p[i], p[i + 1]);
        if (cnt == m) break;
      }
    }
  }
  return 0;
}
