#include<bits/stdc++.h>
using namespace std;
int f[4005][4005];
int sum[40005],a[40005];
int n;
inline int read(){
int x=0,f=1;
char ch=getchar()
#include<bits/stdc++.h>
using namespace std;
int f[4005][4005];
int sum[40005],a[40005];
int n;
inline int read(){
int x=0,f=1;
char ch=getchar()