#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int C = 26;
void add(int &x, int y) {
  x += y;
  while (x >= MOD) x -= MOD;
  while (x < 0) x += MOD;
}
int fix(int x) {
  while (x >= MOD) x -= MOD;
  while (x < 0) x += MOD;
  return x;
}
int pw(int a, int b) {
  int ret = 1;
  while (b) {
    if (b & 1) ret = 1ll * ret * a % MOD;
    b >>= 1;
    a = 1ll * a * a % MOD;
  }
  return ret;
}
const int MAXN = 105;
int n, m, dp[MAXN][MAXN], l[MAXN][MAXN], r[MAXN][MAXN];
void solve() {
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    int k;
    cin >> k;
    for (int rep = 0; rep < k; rep++) {
      int a, b;
      cin >> a >> b;
      --a;
      for (int j = a; j < b; j++) {
        r[i][j] = b;
        l[i][j] = a;
      }
    }
  }
  for (int b = m - 1; ~b; --b) {
    for (int e = b + 1; e <= m; e++) {
      for (int k = b; k < e; k++) {
        int val = 0;
        for (int i = 0; i < n; i++)
          if (b <= l[i][k] && r[i][k] <= e) ++val;
        dp[b][e] = max(dp[b][e], val * val + dp[b][k] + dp[k + 1][e]);
      }
    }
  }
  cout << dp[0][m] << "\n";
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int te = 1;
  for (int w = 1; w <= te; w++) {
    solve();
  }
  return 0;
}
