#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <class t, class u>
void chmax(t& first, u second) {
  if (first < second) first = second;
}
template <class t, class u>
void chmin(t& first, u second) {
  if (second < first) first = second;
}
template <class t>
using vc = vector<t>;
template <class t>
using vvc = vc<vc<t>>;
using pi = pair<int, int>;
using vi = vc<int>;
template <class t, class u>
ostream& operator<<(ostream& os, const pair<t, u>& p) {
  return os << "{" << p.first << "," << p.second << "}";
}
template <class t>
ostream& operator<<(ostream& os, const vc<t>& v) {
  os << "{";
  for (auto e : v) os << e << ",";
  return os << "}";
}
using uint = unsigned;
using ull = unsigned long long;
template <class t, size_t n>
ostream& operator<<(ostream& os, const array<t, n>& first) {
  return os << vc<t>(first.begin(), first.end());
}
template <int i, class T>
void print_tuple(ostream&, const T&) {}
template <int i, class T, class H, class... Args>
void print_tuple(ostream& os, const T& t) {
  if (i) os << ",";
  os << get<i>(t);
  print_tuple<i + 1, T, Args...>(os, t);
}
template <class... Args>
ostream& operator<<(ostream& os, const tuple<Args...>& t) {
  os << "{";
  print_tuple<0, tuple<Args...>, Args...>(os, t);
  return os << "}";
}
template <class t>
void print(t x, int suc = 1) {
  cout << x;
  if (suc == 1) cout << "\n";
  if (suc == 2) cout << " ";
}
ll read() {
  ll i;
  cin >> i;
  return i;
}
vi readvi(int n, int off = 0) {
  vi v(n);
  for (int i = int(0); i < int(n); i++) v[i] = read() + off;
  return v;
}
template <class T>
void print(const vector<T>& v, int suc = 1) {
  for (int i = int(0); i < int(v.size()); i++)
    print(v[i], i == int(v.size()) - 1 ? suc : 2);
}
string readString() {
  string s;
  cin >> s;
  return s;
}
template <class T>
T sq(const T& t) {
  return t * t;
}
void yes(bool ex = true) {
  cout << "Yes"
       << "\n";
  if (ex) exit(0);
}
void no(bool ex = true) {
  cout << "No"
       << "\n";
  if (ex) exit(0);
}
void possible(bool ex = true) {
  cout << "Possible"
       << "\n";
  if (ex) exit(0);
}
void impossible(bool ex = true) {
  cout << "Impossible"
       << "\n";
  if (ex) exit(0);
}
constexpr ll ten(int n) { return n == 0 ? 1 : ten(n - 1) * 10; }
const ll infLL = LLONG_MAX / 3;
const int inf = INT_MAX / 2 - 100;
int topbit(signed t) { return t == 0 ? -1 : 31 - __builtin_clz(t); }
int topbit(ll t) { return t == 0 ? -1 : 63 - __builtin_clzll(t); }
int botbit(signed first) { return first == 0 ? 32 : __builtin_ctz(first); }
int botbit(ll first) { return first == 0 ? 64 : __builtin_ctzll(first); }
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(ll t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }
ll mask(int i) { return (ll(1) << i) - 1; }
bool inc(int first, int second, int c) {
  return first <= second && second <= c;
}
template <class t>
void mkuni(vc<t>& v) {
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());
}
ll rand_int(ll l, ll r) {
  static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
  return uniform_int_distribution<ll>(l, r)(gen);
}
template <class t>
void myshuffle(vc<t>& first) {
  for (int i = int(0); i < int(int(first.size())); i++)
    swap(first[i], first[rand_int(0, i)]);
}
template <class t>
int lwb(const vc<t>& v, const t& first) {
  return lower_bound(v.begin(), v.end(), first) - v.begin();
}
struct unionfind {
  vi p, s;
  int c;
  unionfind(int n) : p(n, -1), s(n, 1), c(n) {}
  int find(int first) {
    return p[first] == -1 ? first : (p[first] = find(p[first]));
  }
  bool unite(int first, int second) {
    first = find(first);
    second = find(second);
    if (first == second) return false;
    p[second] = first;
    s[first] += s[second];
    c--;
    return true;
  }
  bool same(int first, int second) { return find(first) == find(second); }
  int sz(int first) { return s[find(first)]; }
};
void imp() {
  print(-1);
  exit(0);
}
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  cout << fixed << setprecision(20);
  int n, k;
  cin >> n >> k;
  vvc<int> d(n, vi(k));
  for (int i = int(0); i < int(k); i++) {
    for (int j = int(0); j < int(n); j++) {
      cin >> d[j][i];
    }
  }
  vi rs(k, -1);
  for (int i = int(0); i < int(n); i++)
    for (int j = int(0); j < int(k); j++)
      if (d[i][j] == 0) rs[j] = i;
  for (int i = int(0); i < int(k); i++)
    if (rs[i] == -1) imp();
  if (int(rs.size()) != k) imp();
  vi idx(n);
  iota(idx.begin(), idx.end(), 0);
  sort(idx.begin(), idx.end(), [&](int i, int j) { return d[i] < d[j]; });
  unionfind uf(n);
  vvc<int> t(n);
  vc<pi> es;
  auto ae = [&](int first, int second) {
    if (first == -1 || second == -1) {
      imp();
    }
    if (uf.same(first, second)) return;
    void(0);
    uf.unite(first, second);
    es.emplace_back(first, second);
    t[first].push_back(second);
    t[second].push_back(first);
  };
  vc<bool> in(n, 1);
  for (int i = int(0); i < int(n); i++) {
    vi c = d[i];
    for (int j = int(0); j < int(k); j++) c[j]--;
    int to = *lower_bound(idx.begin(), idx.end(), c,
                          [&](int x, const vi& y) { return d[x] < y; });
    if (d[to] == c) {
      ae(to, i);
      in[i] = 0;
    }
  }
  void(0);
  for (int v = int(1); v < int(k); v++) {
    int len = d[rs[0]][v];
    vi ls(len + 1, -1);
    for (int i = int(0); i < int(n); i++)
      if (in[i] && d[i][0] + d[i][v] == len) ls[d[i][0]] = i;
    void(0);
    for (int i = int(0); i < int(len); i++) ae(ls[i], ls[i + 1]);
  }
  void(0);
  if (uf.c != 1) imp();
  void(0);
  for (int r = int(0); r < int(k); r++) {
    vi dist(n, -1);
    queue<int> q;
    auto reach = [&](int v, int d) {
      if (dist[v] != -1) return;
      dist[v] = d;
      q.push(v);
    };
    reach(rs[r], 0);
    while (int(q.size())) {
      int v = q.front();
      q.pop();
      for (auto to : t[v]) reach(to, dist[v] + 1);
    }
    void(0);
    for (int i = int(0); i < int(n); i++)
      if (d[i][r] != dist[i]) {
        imp();
      }
  }
  for (auto e : es) {
    print(e.first + 1, 2);
    print(e.second + 1);
  }
}
