#include <bits/stdc++.h>
using namespace std;
const int maxn = 100005;
int vis[maxn], bid[maxn], sid[maxn], n, m;
vector<int> vec[maxn], big[maxn], small[maxn];
struct Sol {
  int a, b, c;
};
vector<Sol> ans;
int main() {
  scanf("%d%d", &n, &m);
  int tot = 0;
  for (int i = 1; i <= n; i++) {
    int c, t;
    scanf("%d", &c);
    tot += c;
    while (c--) {
      scanf("%d", &t);
      vec[i].push_back(t);
    }
  }
  int bound = (tot + n - 1) / n, all = tot % n, cb = 0, cs = 0;
  for (int i = 1; i <= n; i++) {
    if (vec[i].size() >= bound)
      ++cb, big[cb] = vec[i], bid[cb] = i;
    else
      ++cs, small[cs] = vec[i], sid[cs] = i;
  }
  all = !all ? n - cb : all - cb;
  for (int i = 1; i <= cs; i++) {
    int l = small[i].size(), d = all ? bound : bound - 1;
    for (int j : small[i]) vis[j] = i;
    while (cb > 0 && l < d) {
      vector<int> temp;
      for (int j = big[cb].size() - 1; j >= bound - temp.size() && l < d; j--) {
        if (vis[big[cb][j]] == i)
          temp.push_back(big[cb][j]);
        else
          ans.push_back((Sol){bid[cb], sid[i], big[cb][j]}), ++l,
              vis[big[cb][j]] = i;
        big[cb].pop_back();
      }
      for (int j : temp) big[cb].push_back(j);
      assert(big[cb].size() >= bound);
      if (big[cb].size() == bound) --cb;
    }
  }
  printf("%d\n", ans.size());
  for (Sol s : ans) printf("%d %d %d\n", s.a, s.b, s.c);
  return 0;
}
