#include <bits/stdc++.h>
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast", "unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
const long long inf = numeric_limits<long long>::max() / 2;
const long double eps = 1e-9;
const long double pi = acos(-1);
inline void solve(), read();
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  read();
  solve();
  return 0;
}
long long n, m;
set<pair<long long, long long> > g;
inline void solve() {
  for (long long i = 0; i < 100; i++) {
    vector<long long> a(n);
    iota((a).begin(), (a).end(), 0);
    random_shuffle((a).begin(), (a).end());
    long long ok = 1;
    for (long long i = 0; i < m; i++) {
      if (g.count({a[i % n], a[(i + 1) % n]})) {
        ok = 0;
        break;
      }
    }
    if (!ok) {
      continue;
    }
    for (long long i = 0; i < m; i++) {
      cout << a[i % n] + 1 << " " << a[(i + 1) % n] + 1 << "\n";
    }
    return;
  }
  cout << -1 << "\n";
}
inline void read() {
  cin >> n >> m;
  for (long long i = 0; i < m; i++) {
    long long v, u;
    cin >> v >> u;
    --v, --u;
    g.insert({v, u});
    g.insert({u, v});
  }
}
