#include <bits/stdc++.h>
using namespace std;
int getMin(set<int>& s) {
  set<int>::iterator it = s.begin();
  return *it;
}
int getMax(set<int>& s) {
  set<int>::iterator it = s.end();
  --it;
  return *it;
}
int bits(int x) {
  int r = 0;
  while (x > 0) {
    r += (x & 1);
    x >>= 1;
  }
  return r;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  vector<vector<int> > g(n);
  for (int i = 0; i < m; ++i) {
    int a, b;
    cin >> a >> b;
    --a;
    --b;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  if (n <= 8) {
    int k = (n * (n - 1)) / 2;
    int h = 0;
    vector<pair<int, int> > v(k);
    for (int i = 0; i < n; ++i) {
      for (int j = i + 1; j < n; ++j) {
        v[((2 * n - i - 3) * (i)) / 2 + j - 1] = make_pair(i, j);
      }
    }
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < g[i].size(); ++j) {
        if (i < g[i][j]) {
          int bi = ((2 * n - i - 3) * (i)) / 2 + g[i][j] - 1;
          h = (h | (1 << bi));
        }
      }
    }
    for (int i = 0; i < (1 << k); ++i) {
      if ((h & i) == 0 && bits(i) == m) {
        vector<int> cnt(n, 0);
        for (int j = 0; j < k; ++j) {
          if (i & (1 << j)) {
            ++cnt[v[j].first];
            ++cnt[v[j].second];
          }
        }
        bool pos = true;
        for (int j = 0; j < n; ++j) {
          if (cnt[j] > 2) pos = false;
        }
        if (pos) {
          for (int j = 0; j < k; ++j) {
            if (i & (1 << j)) {
              cout << v[j].first + 1 << " " << v[j].second + 1 << endl;
            }
          }
          return 0;
        }
      }
    }
    cout << -1 << endl;
  } else {
    srand(435423);
    while (true) {
      srand(rand());
      vector<int> ans(1, 0);
      set<int> s;
      for (int i = 1; i < n; ++i) s.insert(i);
      set<int>::iterator it;
      int u = 0, k = 0, mm = m;
      while (mm > 0 && s.size() > 0 && k < 100) {
        bool fi = false;
        k = 0;
        while (!fi && k < 100) {
          int Mi = getMin(s), Ma = getMax(s);
          it = s.upper_bound(rand() % (Ma - Mi + 1) + Mi - 1);
          int r = *it;
          if ((g[u].size() == 0) ||
              (r != g[u][0] && (g[u].size() == 1 || r != g[u][1]))) {
            s.erase(it);
            ans.push_back(r);
            u = r;
            fi = true;
            --mm;
          } else {
            if (k == 99) {
              it = s.begin();
              r = *it;
              if ((g[u].size() == 0) ||
                  (r != g[u][0] && (g[u].size() == 1 || r != g[u][1]))) {
                s.erase(it);
                ans.push_back(r);
                u = r;
                fi = true;
                --mm;
              } else
                ++k;
            } else
              ++k;
          }
        }
      }
      if (mm == 0) {
        for (int i = 0; i < m; ++i) {
          cout << ans[i] + 1 << " " << ans[i + 1] + 1 << endl;
        }
        return 0;
      } else {
        if (s.size() == 0) {
          if ((g[u].size() == 0) ||
              (0 != g[u][0] && (g[u].size() == 1 || 0 != g[u][1]))) {
            ans.push_back(0);
            for (int i = 0; i < m; ++i) {
              cout << ans[i] + 1 << " " << ans[i + 1] + 1 << endl;
            }
            return 0;
          }
        }
      }
    }
  }
}
