#include <algorithm>
#include <iostream>
using namespace std;
const int N = 50000;
const int M = 10;
int *ej[N], eo[N], dd[N], qu[N], ii[N], kk[1 << M];
bool aa[M][M], dp[1 << M], dq[1 << M];
bool check(int i, int j) {
int lower = -1, upper = eo[i];
while (upper - lower > 1) {
int o = lower + upper >> 1;
if (ej[i][o] <= j)
lower = o;
else
upper = o;
}
int o = lower;
return o >= 0 && ej[i][o] == j;
}
int main() {
ios_base::sync_with_stdio(false), cin.tie(NULL);
int n, d_; cin >> n >> d_, d_--;
int cnt = 0;
for (int i = 0; i < n; i++) {
int d; cin >> d, eo[i] = dd[i] = d;
ej[i] = new int[d];
for (int o = 0; o < d; o++) {
int j; cin >> j;
ej[i][o] = j;
}
sort(ej[i], ej[i] + d);
if (d <= d_)
qu[cnt++] = i;
}
int k = 0;
for (int b = 1; b < 1 << d_; b++)
kk[b] = kk[b & b - 1] + 1;
while (cnt) {
int i = qu[--cnt], m = 0; dd[i] = -1;
for (int o = 0; o < eo[i]; o++) {
int j = ej[i][o];
if (dd[j] != -1)
ii[m++] = j;
}
for (int h = 0; h < m; h++) {
aa[h][h] = true;
for (int g = h + 1; g < m; g++)
aa[h][g] = check(ii[h], ii[g]);
}
dp[0] = dq[0] = true;
for (int b = 1, h = 0; b < 1 << m; b++) {
if (1 << h + 1 <= b)
h++;
int b_ = b & b - 1, h_ = kk[(b & -b) - 1];
dq[b] = aa[h_][h] && dq[b_];
dp[b] = dq[b] && dp[b ^ 1 << h];
if (dp[b])
k = max(k, kk[b]);
}
for (int h = 0; h < m; h++) {
int j = ii[h];
if (--dd[j] == d_)
qu[cnt++] = j;
}
}
cout << k + 1 << '\n';
return 0;
}
