#define MAX 1000050
#include <iostream>
#include <vector>
using namespace std;

int ja[MAX];
vector <int> stanky[2000050];

int main(){
	int n, k,su,min, start, end, poc, c, pocetnul, zmrz;
	while(cin >> n >> k){
		for(int i=0; i < MAX; i++){
			ja[i] = 0;
		}
		pocetnul = k;

		for(int j=0; j<n; j++){
			stanky[j].clear();
			stanky[n+j].clear();
			cin >> poc;
			//cout << "poc " << poc << "\n";
			for(int i = 0; i < poc; i++){
				cin >> zmrz;
		///		cout << "pushing " << zmrz << " to " << i << endl;
				stanky[j].push_back(zmrz);
				stanky[n+j].push_back(zmrz);
			}
		}
		/*
		for(int i = 0; i < 2*n; i++){
			//cout << "i:"<< i << " obsah ";
			//cout << "(size: " << stanky[i].size() << ") ";
			//for(int j = 0; j < stanky[i].size(); j++){
			//	cout << stanky[i][j] << " ";
			//}
			//cout << "\n";
		}
		*/

		start = 0;
		end = 0;
		min = 99999999;
		su = 0;

//		while(true){
		while(end < 10) {
			if (pocetnul > 0){
				if (end == 2*n) break;
				for(int i=0; i < stanky[end].size(); i++){
					c = stanky[end][i];
					if(ja[c] == 0) pocetnul--;
					ja[c]++;
					su++;	
				}
				end++;
			} else {
				for(int i=0; i < stanky[start].size(); i++){
					c = stanky[start][i];
					ja[c]--;
					su--;
					if(ja[c] ==0){
						pocetnul++;
					}
				}
				start++;
			}

			if (pocetnul ==0){
				if (min > su) {
					min = su;
				}
			}

		}
		if (min == 99999999) cout << "-1\n";
		else cout << min << "\n";
	}
}