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

#define FOR(i,a,b) for(auto i=a;i<b;++i)
#define F(a) FOR(i,0l,a)
#define FF(a) FOR(j,0l,a)
#define aa first
#define bb second
#define PB push_back
#define pb push_back
#define MOD ((ll)1e9+7)
#define INF (1<<30)
#define LINF (1L<<61)
#define EPS (1e-10)
#define EQ(a,b) (fabs(a-b)<=(fabs(a+b)*EPS))
#ifdef DEBUG
#define DEB puts("DEB!")
#define DPRINT(X) prllf("#X: %d\n",X)
#define dout cout
#else
#define DEB do{}while(0)
#define DPRINT(X) do{}while(0)
#define dout 0 && cout
#endif
using ll=long long;
using ull=unsigned long long;
using ld=double;
using vi=vector<ll>;
using vvi=vector<vi>;
using pii=pair<ll,ll>;

int main(){
  ios::sync_with_stdio(false);cout.tie(0);cin.tie(0);
  while (1) {
    ll n, k;
    cin >> n >> k;
    if (!cin) break;

    vector<int> has(k+1, 0);
    vvi st(2*n);
    for (ll i = 0; i < n; ++ i){ 
      ll l;
      cin >> l;
      st[i].resize(l);
      st[i + n].resize(l);
      for (ll j = 0; j < l; ++ j) {
        cin >> st[i][j];
        st[i + n][j] = st[i][j];
      }
    }
    ll s = 0, e = 0;
    ll cs = 0;
    ll hc = 0;
    ll res = numeric_limits<ll>::max();
    while (1) {
      if (e == st.size() && hc < k) break;
      if (hc >= k && s < e) {
        for (ll i = 0; i < st[s].size(); ++ i) {
          //if (has[st[s][i]]) { has[st[s][i]] --; if (h; }
          has[st[s][i]] --;
          if (!has[st[s][i]]) hc --;
        }
        cs -= st[s].size();
        s ++;
      } else if (e < st.size()) {
        for (ll i = 0; i < st[e].size(); ++ i) {
          //if (!has[st[e][i]]) { has[st[e][i]] = true; hc ++; }
          if (!has[st[e][i]]) hc ++;
          has[st[e][i]] ++;
        }
        cs += st[e].size();
        e ++;
      }
      if (hc >= k) res = min(res, cs);
    }
    cout << (res==numeric_limits<ll>::max()?-1:res) << endl;
  }

  return 0;
}