#include <bits/stdc++.h>
//#define int long long
#define endl "\n"
using namespace std;

using ll = long long;
const int INF = 1e9;
const int MOD = 1e9 + 7;
const int N = 3e3 + 5;

int dp[N][2];
int val[N][20];
int pri[N];

int main() {
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);

    int n, k;
    cin >> n >> k;
    for (int i = 1; i <= n; i++) {
        cin >> pri[i];
        for (int j = 1; j <= pri[i]; j++) {
            cin >> val[i][j];
        }
    }

    for (int i = 1; i <= n; i++) {
        for (int j = k; j >= pri[i]; j--) {
            for (int l = j - 1; l >= j - pri[i]; l--) {
                dp[j][1] = max(dp[j][1], dp[l][0] + val[i][j - l]);
            }
            dp[j][0] = max(dp[j][0], dp[j - pri[i]][0] + val[i][pri[i]]);
            dp[j][1] = max(dp[j][1], dp[j - pri[i]][1] + val[i][pri[i]]);
        }
    }
    cout << max(dp[k][0], dp[k][1]) << endl;

    return 0;
}