#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
const long long mod = 1000000007;
const int mxN = 100010;
vector<int> g[mxN];
int main(int argc, char** argv) {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
  int N, M, u, v;
  cin >> N >> M;
  for (int i = 0; i < M; i++) {
    cin >> u >> v;
    u--, v--;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  vector<int> a;
  for (int i = 0; i < N; i++) a.push_back(i);
  for (int iti = 0; iti < 1000; iti++) {
    shuffle(a.begin(), a.end(), rng);
    int prev = -10;
    vector<pair<int, int> > res;
    for (int i = 0; i + 1 < N && (int)res.size() < M; i++) {
      u = a[i];
      v = a[i + 1];
      bool f = find(g[u].begin(), g[u].end(), v) == g[u].end();
      if (!f && prev == -10) break;
      if (f) {
        res.push_back({u, v});
        if (prev == -10) prev = i;
      } else {
        if (prev != i - 1) {
          bool f2 = find(g[u].begin(), g[u].end(), a[prev]) == g[u].end();
          if (f2) {
            res.push_back({u, a[prev]});
          }
        }
        prev = -10;
      }
    }
    if (prev != -10 && prev != N - 2 && (int)res.size() + 1 == M) {
      u = a[N - 1];
      bool f2 = find(g[u].begin(), g[u].end(), a[prev]) == g[u].end();
      if (f2) {
        res.push_back({u, a[prev]});
      }
      prev = -10;
    }
    if ((int)res.size() == M) {
      for (auto p : res) cout << p.first + 1 << ' ' << p.second + 1 << '\n';
      return 0;
    }
  }
  cout << "-1\n";
  return 0;
}
