#include<bits/stdc++.h>
using namespace std;
inline int read(){
	register int x=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		x=(x<<1)+(x<<3)+(ch^48);
		ch=getchar();
	}
	return x*f;
}
struct star{
	int x,y;
}a[501];
int n,k,ans,dp[501][501];
bool cmp1(star u,star v){
	if(u.x==v.x) return u.y<v.y;
	else return u.x<v.x;
}
bool cmp2(star u,star v){
	if(u.y==v.y) return u.x<v.x;
	else return u.y<v.y;
}
int main(){
	n=read(),k=read();
	for(int i=1;i<=n;i++) a[i].x=read(),a[i].y=read();
	sort(a+1,a+1+n,cmp1);
	memset(dp,0x3f,sizeof(dp));
	for(int i=1;i<=n;i++) dp[i][0]=dp[i][1]=0;
	for(int i=1;i<=n;i++){
		for(int l=1;l<=i;l++){
			for(int j=1;j<i;j++){
				if(a[i].x>=a[j].x&&a[i].y>=a[j].y&&(long long)dp[j][l-1]+a[i].x-a[j].x+a[i].y-a[j].y-1<=k) dp[i][l]=min(dp[i][l],dp[j][l-1]+a[i].x-a[j].x+a[i].y-a[j].y-1);
			}
		}
	}
	for(int i=1;i<=n;i++){
		for(int l=0;l<=n;l++) if(dp[i][l]<=k) ans=max(ans,l);
	}
	sort(a+1,a+1+n,cmp2);
	memset(dp,0x3f,sizeof(dp));
	for(int i=1;i<=n;i++) dp[i][0]=dp[i][1]=0;
	for(int i=1;i<=n;i++){
		for(int l=1;l<=i;l++){
			for(int j=1;j<i;j++){
				if(a[i].x>=a[j].x&&a[i].y>=a[j].y&&(long long)dp[j][l-1]+a[i].x-a[j].x+a[i].y-a[j].y-1<=k) dp[i][l]=min(dp[i][l],dp[j][l-1]+a[i].x-a[j].x+a[i].y-a[j].y-1);
			}
		}
	}
	for(int i=1;i<=n;i++){
		for(int l=0;l<=n;l++) if(dp[i][l]<=k) ans=max(ans,l);
	}
	printf("%d",ans+k);
    return 0;
}

(long long)dp[j][l-1]+a[i].x-a[j].x+a[i].y-a[j].y-1<=k 这样怎么爆的