#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <utility>
using namespace std;
const int maxN = 304;
int x[maxN], y[maxN];
int n;
vector< pair<int, int> > p;
bool mark[maxN][maxN];
int dist(const int& i, const int& j)
{
return (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]);
}
bool compairation(const pair<int, int>& p1, const pair<int, int>& p2)
{
return (dist(p1.first, p1.second) > dist(p2.first, p2.second));
}
int ccw(const int& i, const int& j, const int& k)
{
int dx1 = x[j] - x[i], dy1 = y[j] - y[i];
int dx2 = x[k] - x[j], dy2 = y[k] - y[j];
return (dx1 * dy2 - dx2 * dy1);
}
int main()
{
cin >> n;
for (int i = 1; i <= n; i++)
cin >> x[i] >> y[i];
for (int i = 1; i < n; i++)
for (int j = i + 1; j <= n; j++)
p.push_back(pair<int, int>(i, j));
sort(p.begin(), p.end(), compairation);
memset(mark, true, sizeof(mark));
double total = 0.0;
for (int i = 0; i < p.size(); i++)
if (mark[p[i].first][p[i].second])
{
int d = p[i].first, c = p[i].second;
vector<int> point;
point.clear();
for (int j = 1; j <= n; j++)
if (ccw(d, j, c) == 0) point.push_back(j);
for (int u = 0; u < point.size(); u++)
for (int v = u + 1; v < point.size(); v++)
{
mark[point[u]][point[v]] = false;
mark[point[v]][point[u]] = false;
//cout << point[u] << " " << point[v] << endl;
}
total += sqrt(double(dist(d, c)));
}
cout << round(total) << endl;
return 0;
}
