#include "mountains.h"
#define x first
#define y second
using namespace std;
typedef pair<long long,long long> point;
const int MAX = 2005;
int dp[MAX][MAX];
point p[MAX];
long long ccw(point a, point b, point c)
{
return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
}
int maximum_deevs(vector<int> y)
{
int n = y.size();
for (int i = 0; i < n; i++)
{
p[i].y = y[i];
p[i].x = i;
}
for (int r = 0; r < n; r++)
{
int sum = 0, last = r;
dp[r][r] = 1;
for (int l = r - 1; l >= 0; l--)
{
dp[l][r] = dp[l][r - 1];
if (ccw(p[l], p[last], p[r]) >= 0)
{
sum += dp[l + 1][last-1];
last = l;
}
dp[l][r] = max(dp[l][r], 1 + sum + dp[l][last-1]);
}
}
return dp[0][n-1];
}
