#include <cstdio>

using namespace std;

bool pole[2005][2005];

int main()
{
	int N;
	int res = 0;

	scanf("%d", &N);

	int x[N], y[N];
	for (int i = 0; i < N; i++)
	{
		scanf("%d %d", &x[i], &y[i]);
		pole[x[i] + 1000][y[i] + 1000] = 1;
	}

	bool breakAll = false;
	for (int i = 1; i < N; i++)
	{
		int dx = x[0] - x[i];
		int dy = y[0] - y[i];

		for (int j = 0; j < N; j++)
		{
			if (pole[x[j] + dx + 1000][y[j] + dy + 1000])
				continue;

			if (pole[x[j] - dx + 1000][y[j] - dy + 1000])
				continue;

			breakAll = true;
			break;
		}

		if (breakAll)
			continue;
		
		//over ci posun je ok
		res += 2;
	}

	for (int i = 0; i < N; i++)
		pole[x[i] + 1000][y[i] + 1000] = 0;

	printf("%d\n", res);

	return 0;
}