#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  for (; ch < '0' || ch > '9'; ch = getchar())
    if (ch == '-') f = -1;
  for (; ch >= '0' && ch <= '9'; ch = getchar())
    x = (x << 1) + (x << 3) + ch - 48;
  return x * f;
}
vector<int> b;
map<pair<int, int>, int> mp;
int n, m;
int main() {
  n = read(), m = read();
  srand(233333);
  for (int i = 1; i <= n; i++) b.push_back(i);
  for (int i = 1; i <= m; i++) {
    int x = read(), y = read();
    if (x > y) swap(x, y);
    mp[make_pair(x, y)] = 1;
  }
  for (int tot = 1; tot <= 100; tot++) {
    random_shuffle(b.begin(), b.end());
    bool flag = 1;
    for (int i = 0; i < m; i++) {
      int p = b[i], q = b[(i + 1) % n];
      if (p > q) swap(p, q);
      if (p == q) {
        flag = 0;
        break;
      }
      if (mp[make_pair(p, q)]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      for (int i = 0; i < m; i++) printf("%d %d\n", b[i], b[(i + 1) % n]);
      return 0;
    }
  }
  puts("-1");
  return 0;
}
