#include <iostream>
#include <vector>
#include <cmath>

int main()
{
	int n;
	int64_t K;
	std::cin >> n >> K;
	std::vector<int64_t> xs(n);
	std::vector<int64_t> ys(n);
	for (int i = 0; i < n; i++)
	{
		std::cin >> xs[i] >> ys[i];
	}

	long double bestdiam = 0;
	int count = 0;
	int j = 0;
	for (int i = 0; i < n; i++)
	{
		int ip1 = (i + 1) % n;
		int64_t dx = xs[ip1] - xs[i];
		int64_t dy = ys[ip1] - ys[i];
		while (true)
		{
			int64_t dx1 = xs[j] - xs[i];
			int64_t dy1 = ys[j] - ys[i];
			int64_t area1 = dx * dy1 - dy * dx1;
			long double dist = std::sqrt((long double)(dx1 * dx1 + dy1 * dy1));
			int nextj = (j + 1) % n;

			if (dist > bestdiam)
			{
				bestdiam = dist;
				count = 0;
			}

			if (nextj != i && j != ((i + 1) % n) && dist == bestdiam)
			{
				count++;
			}

			int64_t dx2 = xs[nextj] - xs[i];
			int64_t dy2 = ys[nextj] - ys[i];
			int64_t area2 = dx * dy2 - dy * dx2;
			if (area2 < area1)
				break;
			else
				j = nextj;
		}
	}

	count /= 2;

	long double ans = std::ceil(K / 2.0 / bestdiam);

	if (2.0 * ans * bestdiam == K && ans > count)
		ans += 1.0;

	std::cout << int64_t(ans) << std::endl;
}