#include <bits/stdc++.h>
using namespace std;
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};
const int inf = 0x7f7f7f7f;
const int mod = 1000000007;
const double eps = 1e-8;
int n, m;
set<int> v;
vector<pair<int, int> > ans;
vector<int> vc[100007];
bool isok(int u, int v) {
  for (size_t i = 0; i < vc[u].size(); ++i) {
    if (vc[u][i] == v) return false;
  }
  return true;
}
bool dfs(int u) {
  if ((int)ans.size() == min(n - 1, m)) return true;
  v.erase(u);
  for (set<int>::iterator it = v.begin(); it != v.end(); ++it) {
    if (!isok(u, *it)) continue;
    ans.push_back(make_pair(u, *it));
    if (dfs(*it))
      return true;
    else {
      ans.pop_back();
      it = v.find(*it);
    }
  }
  v.insert(u);
  return false;
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i <= n; ++i) vc[i].clear();
  int x, y;
  for (int i = 0; i < m; ++i) {
    scanf("%d%d", &x, &y);
    vc[x].push_back(y);
    vc[y].push_back(x);
  }
  for (int i = 1; i <= n; ++i) v.insert(i);
  ans.clear();
  for (int i = 1; i <= n; ++i) {
    if (dfs(i)) {
      if (m == n) ans.push_back(make_pair(ans[0].first, ans.back().second));
      for (int i = 0; i < m; ++i)
        printf("%d %d\n", ans[i].first, ans[i].second);
      return 0;
    }
  }
  printf("-1\n");
  return 0;
}
