#include<iostream>
using namespace std;
    int shu[5001][5001]={0};
    int dp[5001],Max[5001];
    int n,h,delta,p,q;
int main()
{
    cin>>n>>h>>delta;
    for(int i=1;i<=n;i++)
    {
        cin>>p;
        for(int j=1;j<=p;j++)
        {
            cin>>q;
            shu[i][q]++;
        }
    }
    
    for(int y=h;y>=1;y--)
    {
        for(int k=1;k<=n;k++)
        {
                dp[k]=max(dp[k]+shu[k][y],shu[k][y]+Max[y+delta]);
             if(dp[k]>=Max[y])
               Max[y]=dp[k];
        }
    }
    cout<<Max[1];
    return 0;
}

DP:
f[i][j]表示高度为i在第j棵树上的情况
mx[i]表示该层最大值
转移方程:f[i][j]=max(mx[i+delta],f[i+1][j])+a[j][i]
Code:
```C++
//
// main.cpp
// 雷涛的小猫
//
// Created by stneng on 16/5/26.
// Copyright © 2016年 stneng. All rights reserved.
//

#include <cstdio>
const int N=5000;
int n,h,delta,nn[N],a[N][N],f[N][N],mx[N];
inline int read(){
int x=0;char ch=getchar();
while (ch>'9'||ch<'0') ch=getchar();
while (ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x;
}
int main() {
// insert code here...std::cout << "Hello, World!\n";
n=read();h=read();delta=read();
int x;
for (int i=1;i<=n;i++) {
nn[i]=read();
for (int j=1;j<=nn[i];j++) {
x=read();
a[i][x]++;
}
}
for (int i=h;i>=1;i--)
for (int j=1;j<=n;j++){
f[i][j]=mx[i+delta]>f[i+1][j]?mx[i+delta]:f[i+1][j];
f[i][j]+=a[j][i];
if (f[i][j]>mx[i]) mx[i]=f[i][j];
}
printf("%d\n",mx[1]);
return 0;
}
```

DP:
f[i][j]表示高度为i在第j棵树上的情况
mx[i]表示该层最大值
转移方程:f[i][j]=max(mx[i+delta],f[i+1][j])+a[j][i]
Code:
```C++
//
// main.cpp
// 雷涛的小猫
//
// Created by stneng on 16/5/26.
// Copyright © 2016年 stneng. All rights reserved.
//

#include <cstdio>
const int N=5000;
int n,h,delta,nn[N],a[N][N],f[N][N],mx[N];
inline int read(){
int x=0;char ch=getchar();
while (ch>'9'||ch<'0') ch=getchar();
while (ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x;
}
int main() {
// insert code here...std::cout << "Hello, World!\n";
n=read();h=read();delta=read();
int x;
for (int i=1;i<=n;i++) {
nn[i]=read();
for (int j=1;j<=nn[i];j++) {
x=read();
a[i][x]++;
}
}
for (int i=h;i>=1;i--)
for (int j=1;j<=n;j++){
f[i][j]=mx[i+delta]>f[i+1][j]?mx[i+delta]:f[i+1][j];
f[i][j]+=a[j][i];
if (f[i][j]>mx[i]) mx[i]=f[i][j];
}
printf("%d\n",mx[1]);
return 0;
}
```

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