#include <bits/stdc++.h>

using namespace std;

int n, m;
vector<vector<int> > shops;


int analyze_shop(int i, int limit){
  set<int> creams;
  int total = 0;
  
  int j = i;
  do{
    int size = shops[j].size();
    for(int q=0; q<size; q++){
      creams.insert(shops[j][q]);
      total++;
    }
    if(limit != -1 && total > limit)break;
    j = (j+1) % n;
  }while(i!=j && creams.size() < m);
  
  return creams.size() < m ? -1 : total;
}


int main(){
  ios::sync_with_stdio(false);
  
  while(scanf("%d %d\n", &n, &m) == 2) {
    shops.clear();
	for(int i=0; i<n; i++){
	  vector<int> shop;
	  int c;
	  scanf("%d", &c);
	  for(int j=0; j<c; j++){
	    int d;
	    scanf(" %d", &d);
	    shop.push_back(d);
	  }
	  shops.push_back(shop);
	}
	
	int min = analyze_shop(0, -1);
	for(int i=1; i<n; i++){
	  if(min == -1)break;
	  
	  int len = analyze_shop(i, min);
	  if(len==-1)continue;
	  min = len < min ? len : min;
	}
	
	cout << min << endl;
  }
  
  return 0;
}