#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;
const double PI = acos(-1.0);
const long double eps = 1e-6;
const int mod = 1e9 + 7;
const int maxn = 200 + 10;
const int N = 1e6 + 10;
const int M = N * 20;
const long long mm = (1LL << 32);
template <class T>
inline void read(T &x) {
  x = 0;
  char c = getchar();
  bool f = 0;
  for (; !isdigit(c); c = getchar()) f ^= c == '-';
  for (; isdigit(c); c = getchar()) x = x * 10 + (c ^ 48);
  x = f ? -x : x;
}
template <class T>
inline void write(T x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  T y = 1;
  int len = 1;
  for (; y <= x / 10; y *= 10) ++len;
  for (; len; --len, x %= y, y /= 10) putchar(x / y + 48);
}
long long qpow(long long a, long long b, long long MOD) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % MOD;
    b >>= 1;
    a = (a * a) % MOD;
  }
  return ans;
}
map<pair<int, int>, int> s;
int ans[100004];
int main() {
  int n, m;
  while (~scanf("%d%d", &n, &m)) {
    s.clear();
    for (int i = 0; i < m; i++) {
      int x, y;
      scanf("%d%d", &x, &y);
      s[make_pair(x, y)] = 1;
      s[make_pair(y, x)] = 1;
    }
    for (int i = 1; i <= n; i++) {
      s[make_pair(i, i)] = 1;
    }
    int flag = 0;
    for (int i = 1; i <= n; i++) ans[i] = i;
    int t = 500;
    while (t--) {
      random_shuffle(ans + 1, ans + 1 + n);
      ans[0] = ans[n];
      int cnt = 0;
      for (int i = 0; i < n; i++) {
        if (s[make_pair(ans[i], ans[i + 1])]) continue;
        cnt++;
      }
      if (cnt < m) continue;
      flag = 1;
      for (int i = 0; i < n; i++) {
        if (s[make_pair(ans[i], ans[i + 1])] == 1) continue;
        if (m) {
          m--;
          printf("%d %d\n", ans[i], ans[i + 1]);
        }
      }
      break;
    }
    if (flag == 0) printf("-1\n");
  }
}
