#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define pb push_back
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ii = pair<int,int>;
using iii = tuple<int,int,int>;
const int inf = 2e9+1;
const int mod = 1e9+7;
const int maxn = 1e5+100;
template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }
int dp[2001][2001], y[2001];
bool pode[2001][2001];
int maximum_deevs(vector<int>v){
int n = sz(v);
for(int i=0;i<n;++i){
y[i+1] = v[i];
ll bx = 0, by = 0;
for(int j=i+1;j<n;++j){
if(bx*ll(v[j]-v[i])<by*ll(j-i))pode[i+1][j+1] = 1;
else bx = ll(j-i), by = ll(v[j]-v[i]);
}
}
for(int r=1;r<=n;++r){
dp[r][r] = 1;
int sum = 0, last = r;
for(int l=r-1;l>=1;--l){
dp[l][r] = dp[l][r-1];
if(pode[l][r]==0){
sum += dp[l+1][last-1], last = l;
}
ckmax(dp[l][r], sum + 1 + dp[l][last-1]);
}
}
return dp[1][n];
}
