#include<bits/stdc++.h>
using namespace std;
using ll = long long;

#define D if(0)

const int NMAX = 1123;

struct Bod
{
	int x=0,y=0;
	Bod(int X,int Y): x(X),y(Y)
	{
	}
	Bod():Bod(0,0){}
	Bod operator + (Bod & dr)
	{
		return Bod(x+dr.x,y+dr.y);
	}
	Bod operator - (Bod & dr)
	{
		return Bod(x-dr.x,y-dr.y);
	}
	bool operator == (const Bod & dr) const
	{
		return x==dr.x && y==dr.y;
	}
	bool operator < (const Bod & dr) const
	{
		if(x==dr.x) return y<dr.y;
		return x<dr.x;
	}
};

Bod b[NMAX];
set<Bod> setB;
int n;

int main()
{
	int out=0;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		scanf("%d%d",&(b[i].x),&(b[i].y));
	}
	sort(b,b+n);
	for(int i=0;i<n;i++)
		setB.insert(b[i]);
	for(int i=1;i<n;i++)
	{
		Bod v = b[0]-b[i];
		bool isOk = 1;
		for(int j=0;j<n;j++)
		{
			if(!(setB.count(b[j]+v) || setB.count(b[j]-v)))
			       isOk = 0;	
		}
		if(isOk) out++;
		
	}
	printf("%d\n",2*out);
}