#include <bits/stdc++.h>

using namespace std;

int main () {
	ios::sync_with_stdio(false);

	long long n, k;
	
	while ( cin >> n >> k ) {
		vector<pair< set <long long > , long long > > in;
		unordered_map< long long, long long > part;
		long long sum = 0, iL = 0, iR = 0, diff = 0;
		long long mini = 0x7fffffff;
		bool solved = false;
		bool ctr = false;
		bool start = true;
		for ( long long i = 0; i < n; ++i ) {
			long long x, cnt = 0;
			cin >> x;
			set <long long> samples;
			for ( long long j = 0; j < x; ++j ) {
				long long y;
				cin >> y;
				if ( samples.insert(y).second == true )
					++cnt;
			}
			in.push_back({samples, x});		
		}
		
		while ( start || iL != 0 ) {
			for ( auto i : in[iR].first ) {
				++part[i]; 
				if ( part[i] == 1 )
					++diff;
			}
			sum += in[iR].second;
			//cout << diff << " " << iL << " " << iR << endl;
			while( diff == k ) {
				mini = min(sum, mini);
				solved = true;
				for( auto n : in[iL].first) {
					--part[n];
					if( part[n] == 0) {
						--diff;
					}
				}
				sum -= in[iL].second;
				++iL;
				if( iL == n ) {
					iL = 0;
					start = false;
					break;
				}
				//cout << diff << " " << k << endl;	
			}
			++iR;
			if( iR == n) {
				ctr = true;
				iR = 0;
			}
			
			if( iR == iL && ( iL == 0 || ctr ) ) {
				break;
			}
				
		}	
		if(solved)
			cout << mini << endl;
		else 
			cout << -1 << endl;



	}
	return 0;
}