#include<bits/stdc++.h>
#define int long long
#define ull unsigned long long
using namespace std;
typedef pair<int,int>PII;
typedef pair<int,PII>PPI;
typedef array<int,3>ar;
typedef __int128 i28; 
const int N=3000+100;
const int N1=1e9+9;
const int M=998244353;
const ull mask = std::chrono::steady_clock::now().time_since_epoch().count();
mt19937_64 rng(time(0));
const int M1=19260817;
const int base=233;
const int base1=131;
const int INF = 0x3f3f3f3f;
int val[N][N];
int p[N];
int dp[N][N];
void solve()
{
	int n,k;	
	cin>>n>>k;
	for(int i=1;i<=n;i++)
	{
		cin>>p[i];
		for(int j=1;j<=p[i];j++)
		{
			cin>>val[i][j];
		}
	}
	for(int i=1;i<=n;i++)
	{
		for(int j=p[i];j<=k;j++)
		{
			if(dp[i-1][j-p[i]]==0&&j-p[i]!=0) continue;
			dp[i][j]=max(dp[i-1][j],dp[i-1][j-p[i]]+val[i][p[i]]);
		}
	}
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=p[i];j++)
		{
			if(k<j) continue;
			if(dp[n][k-j]==0&&k!=j) continue;
			dp[n][k]=max(dp[n][k],dp[n][k-j]+val[i][j]);
		}
	}
	cout<<dp[n][k]<<"\n";
}
signed main()
{
	std::ios::sync_with_stdio(false);
	cout.tie(0);cin.tie(0);
	int _=1;
//	cin>>_;
	while(_--)
	{
		solve();
	}
}