#include<bits/stdc++.h>
using namespace std;
int n, k;
struct nod {
	int x, y;
}a[510];
bool tmp(nod a, nod b) {
	if (a.x != b.x)return a.x < b.x;
	return a.y < b.y;
}
int d[510][510];//欧几里得距离
int f[510][110];//状态
int ans;
int main() {
	scanf("%d %d", &n, &k);
	for (int i = 1; i <= n; i++)scanf("%d %d", &a[i].x, &a[i].y);
	sort(a + 1, a + n + 1, tmp);
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j < i; j++) {
			if (a[i].x < a[j].x || a[i].y < a[j].y)d[i][j] = -1;
			else d[i][j] = a[i].x - a[j].x + a[i].y - a[j].y;
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int m = 0; m <= k; m++) {
			f[i][m] = m + 1;
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j < i; j++) {
			if (d[i][j] == -1)continue;
			for (int m = 0; m <= k; m++) {
				if (d[i][j] == 1)f[i][m] = max(f[i][m], f[j][m] + 1);
				else if (m >= d[i][j] - 1) {
					f[i][m] = max(f[i][m], f[j][m - d[i][j] + 1] + d[i][j]);
				}
			}
		}
	}
	for (int i = 1; i <= n; i++)ans = max(ans, f[i][k]);
	printf("%d", ans);
	return 0;
}