#include <cstdio>
#include <algorithm>
using namespace std ;
struct eng
{
int x,y;
};
bool comp (eng i,eng j)
{
return i.y<j.y;
}
int min1,s,n,w,i,j,k;
eng a[1001];
int c[1001];
int main ()
{
freopen ("energii.in","r",stdin);
freopen ("energii.out","w",stdout);
scanf("%d%d",&n,&w);
min1=10000001;
for (i=1;i<=n;i++)
scanf ("%d%d",&a[i].x,&a[i].y);
sort (a,a+n+1,comp);
for (i=n;i>=2;i--)
{
	c=a[i].y;
	s=a[i].x;
	k=1;
	c[i]=k;
	if (s<min1 && c<w)
	for (j=i-1;j>=1;j--)
		if (s+a[j].x<min1 && c+a[j].y<w)
			{
				c[j]=k+1;
				k=k+1;
		}
	else if (s<min1)
		min1=s;
}
printf("%d",min1);
return 0;
}