#include <bits/stdc++.h>

using namespace std;

int solve(int N, int K);

int main(){
    std::ios::sync_with_stdio(false);
    int N, K;
        
    while(cin >> N){    
        int K;
        cin >> K;
        int ans = solve(N, K);
        cout << ans << endl;
    }
}

void compute_add(vector<int>& ntypes, int& ndiff_types, vector<int>& vals, int& nall) {
    for (auto a : vals) {
        ntypes[a]++;
        if (ntypes[a] == 1)
            ndiff_types++;
    }
    
    nall += vals.size();
}

void compute_remove(vector<int>& ntypes, int& ndiff_types, vector<int>& vals, int& nall) {
    for (auto a : vals) {
        ntypes[a]--;
        if (ntypes[a] == 0)
            ndiff_types--;
    }
    
    nall -= vals.size();
}

int solve(int N, int K) {
    vector<vector<int>> stands;
    stands.reserve(N);
    
    for (int i = 0; i < N; ++i) {
        int L;
        cin >> L;
        vector<int> stand(L, 0);
        for (int j = 0; j < L; ++j) {
            int t;
            cin >> t;
            stand[j] = t-1;
        }
        
        stands.push_back(stand);
    }
     
    int ndiff_types{0};
    int nall{0};
    vector<int> ntypes(K, 0);
    int best = numeric_limits<int>::max();
    
    // N >= 2
    for (int left = 0, right = 0; right <= (2*N + 1);) {
        if (ndiff_types == K) {
            best = min(best, nall);
                       
            int i = left%N;
            compute_remove(ntypes, ndiff_types, stands[i], nall);
            left++;
        } else {
            int i = right%N;
            compute_add(ntypes, ndiff_types, stands[i], nall);
            right++;
        }
    }
    
    if (best == numeric_limits<int>::max())
        return -1;
    else
        return best;
}