#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sqr(a) (a * a)
typedef pair <int, int> ii;
const int N = 2005;
int dp[N][N];
int cross(ii a, ii b) {
return a.first * b.second - a.second * b.first;
}
bool ccw(ii a, ii b, ii c) {
return cross(ii(b.first - a.first, b.second - a.second), ii(c.first - a.first, c.second - a.second)) > 0;
}
int maximum_deevs(vector <int32_t> y) {
int n = y.size(), ret = 0;
for (int mask = 0; mask < (1 << n); ++mask) {
int t = __builtin_popcount(mask);
for (int i = 0; i < n; ++i) if (mask & (1 << i)) {
for (int j = i + 1; j < n; ++j) if (mask & (1 << j)) {
bool ok = false;
for (int k = i + 1; k < j; ++k) if (ccw(ii(j, y[j]), ii(k, y[k]), ii(i, y[i]))) {
ok = true;
}
if (!ok) t = -1;
}
}
ret = max(ret, t);
}
return ret;
}
