#include <iostream>
#include <set>
#include <vector>

using namespace std;

int main() {
	ios::sync_with_stdio(false);
	int samples[1000001];
	int n, k;
	while(cin >> n >> k) {
		for(int i = 0; i <= k; i++) samples[i] = 0;
		set<int> stuff;
		vector<vector<int> > stands(n);
		for(int stand = 0; stand < n; stand++) {
			int l;
			cin >> l;
			stands[stand] = vector<int>(l);
			for(int i = 0; i < l; i++) cin >> stands[stand][i];
		}

		int start = 0;
		int end = 0;
		int result = 0;
		int best_result = 0;
		
		while(stuff.size() < k && end < n) {
			for(vector<int>::iterator it = stands[end].begin(); it != stands[end].end(); it++) {
				samples[*it]++;
				result++;
				stuff.insert(*it);
			}
			end++;
		}

		best_result = result;
		
		if(stuff.size() < k) {
			cout << -1 << endl;
			continue;
		}

		bool moved_start = false;

		while(!moved_start || start != 0) {			
			int i = 0;
			while(i < stands[start].size()) {
				if(samples[stands[start][i]] == 1) break;
				result--;
				samples[stands[start][i]]--;
				i++;
			}
			if(i == stands[start].size()) {
				moved_start = true;
				start = (start + 1) % n;
				best_result = min(result, best_result);
				continue;
			}

			i--;
			//Revert move of start
			while(i != -1) {
				result++;
				samples[stands[start][i]]++;
				i--;
			}

			for(vector<int>::iterator it = stands[end].begin(); it != stands[end].end(); it++) {
				samples[*it]++;
				result++;
			}
			end = (end + 1) % n;
			
		}

		//for(int stand = 0; stand < n; stand++) stands[stand].clear();

		cout << best_result << endl;
		
	}
	return 0;
}