#include <bits/stdc++.h>
#define fir first
#define sec second
typedef std::pair<int,int> pii;

const int maxn = 505;
const int maxm = 105;
int n,k,f[maxn][maxm];
pii a[maxn];

int main() {
	freopen("csp2022pj_point.in","r",stdin);
	freopen("csp2022pj_point.out","w",stdout);
	scanf("%d %d",&n,&k);
	for(int i = 1;i <= n;++ i) {
		scanf("%d %d",&a[i].fir,&a[i].sec);
		for(int j = 0;j <= k;++ j)
			f[i][j] = 1;
	}
	std::sort(a + 1 , a + 1 + n);
	for(int i = 1;i <= n;++ i) {
		for(int p = i - 1;p;-- p) {
			if(a[p].fir > a[i].fir||a[p].sec > a[i].sec)continue ;
			int val = std::abs(a[i].fir - a[p].fir) + std::abs(a[i].sec - a[p].sec) - 1;
			if(val > k)continue ;
			for(int j = val;j <= k;++ j) {
				f[i][j] = std::max(f[i][j] , f[p][j - val] + 1);
			}
		}
	}
	int ans = 0;
	for(int i = 1;i <= n;++ i)ans = std::max(ans , f[i][k]);
	printf("%d",ans + k);
	return 0;
}