#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <sstream>
#include <queue>
#include <algorithm>
#include <cmath>

#define lol long long

using namespace std;

bool is_good(int a, int b, int c)
{
  return a * b >= c && a + b - 1 <= c;
}

struct Coord
{
  int x, y, z;

  int get_coord(int i)
  {
    if (i == 0)
      return x;
    if (i == 1)
      return z;
    if (i == 2)
      return y;
  }
};

int main()
{
  int d[3];
  cin >> d[0] >> d[1] >> d[2];

  vector<int> v{0,1,2};
  vector<int> good_perm;
  do
  {
    if (d[v[0]] <= d[v[1]] && d[v[1]] <= d[v[2]])
    {
      good_perm = v;
      break;
    }
  } while (next_permutation(v.begin(), v.end()));


  sort(d, d + 3);

  int a = d[0];
  int b = d[1];
  int c = d[2];

  if (a * b < c)
    return cout << -1, 0;

  vector<Coord> ans;
  int cur = -99;
  int A = a;
  for (int i = 0; i < A-1; ++i)
  {
    if (!is_good(a, b, c))
    {
      ans.push_back({ cur, cur, cur });
      cur++;
      --a, --b, --c;
    }
    else
    {
      for (int i = 0; i < a; ++i)
        ans.push_back({ cur + i, cur, cur });
      for (int i = 1; i < b; ++i)
        ans.push_back({ cur, cur + i, cur });
      c -= a + b - 1;
      for (int i = 0; i < a-1; ++i)
      {
        if (!c)
          break;
        for (int j = 0; j < b - 1; ++j)
        {
          if (!c)
            break;

          ans.push_back({ cur + i + 1, cur + j + 1, cur });
          --c;
        }
      }
      a = b = c = 0;
      break;
    }
  }

  if (a == 1 && b != c)
    cout << "HUI2\n";

  if (a == 1)
  {
    for (int j = 0; j < b; ++j)
      ans.push_back({ cur, cur + j, cur });
    a = b = c = 0;
  }

  if (a || b || c)
    cout << "HUI\n";

  cout << ans.size() << "\n";
  for (int i = 0; i < ans.size(); ++i)
  {
    for (int j = 0; j < 3; ++j)
      for (int k = 0; k < good_perm.size(); ++k)
        if (good_perm[k] == j)
          cout << ans[i].get_coord(k) << " ";
    cout << "\n";
  }
}
/*
1
7 16
1 2
2 1
1 3 3 1
2 4 4 2
3 4 4 3
4 5 5 7 7 6 6 4
6 7
4 6
7 5
5 4



*/