#include <bits/stdc++.h>
using namespace std;

#define PB push_back
#define CL(A, I) (memset(A, I, sizeof(A)))
#define D(X) cout<<"  "<<#X": "<<X<<endl;
#define FOR(i, m, n) for(int i(m); i < n; i++)
#define F(n) FOR(i, 0, n)
#define FF(n) FOR(j, 0, n)
#define aa first
#define bb second

typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll, ll> ii;
typedef vector<ii> vii;

int n,k;
vector<int> st[2000007];
int cntk[1000007];
int cntg, cntb;

int main() {
	ios::sync_with_stdio(0);
	
	while(cin>>n>>k) {
		F(2*n+5)st[i].clear();
		CL(cntk,0);
		F(n){
			int L;
			cin>>L;
			FF(L){
				int x;
				cin>>x;
				st[i].PB(x);
				st[n+i].PB(x);
			}
		}
		int lemin=-1;
		
		cntg=0;
		cntb=0;	
			
		int l=0;
		int r=0;
		while(r<2*n){
			
			while(r<2*n&&r-l<n && cntg<k) {
				for(int x : st[r]) {
					if(cntk[x]==0)cntg++;
					cntk[x]++;
				}
				cntb+=st[r].size();
				r++;
			}
			
			
			if(cntg==k){

				if(lemin==-1)lemin=cntb;
				lemin=min(lemin,cntb);
			}
			if(l==0&&r==n&&cntg!=k)break;
			//cout<<l<<' '<<r<<endl;
			
			while(l<r&&cntg==k){
				//cout<<'r'<<l<<' '<<r<<endl;
					
				for(int x : st[l]) {
					cntk[x]--;
					if(cntk[x]==0)cntg--;						
				}
				cntb-=st[l].size();
				if(cntg==k){

					if(lemin==-1)lemin=cntb;
					lemin=min(lemin,cntb);
				}
				l++;
			}	
			
		//cout<<"xx"<<l<<' '<<r<<endl;			

		}
			cout<<lemin<<endl;	
		}

	}