//dp[i][j] = max(dp[i][j],dp[i][j+1]+a[i][j])
//dp[i][j] = max(dp[i][j],dp[k][j+delta]+a[i][j])

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

const int N = 2005;
int a[N][N],dp[N][N],n,h,delta;
int p[N];

int main()
{
    cin >> n >> h >> delta;
    for(int i=1;i<=n;i++)
    {
        int t;
        cin >> t;
        for(int j=1;j<=t;j++)
        {
            int p;
            cin >> p;
            a[i][p]++;
        }
    }
    int maxn = 0;
    dp[1][h] = a[1][h];
    for(int j=h;j>=0;j--)
    {
        for(int i=1;i<=n;i++)
        {
            dp[i][j] = max(dp[i][j],dp[i][j+1]+a[i][j]);
            dp[i][j] = max(dp[i][j],p[j+delta]+a[i][j]);
            p[j] = max(p[j],dp[i][j]);
            maxn = max(maxn,dp[i][j]);
        }
    }
    cout << maxn;
    return 0;
}