#include<math.h>
#include<stdio.h>

int p1,aux,p2,max,n,wr,a[20005],min,j,i;

int main()
{
freopen("energii.in","r",stdin);
freopen("energii.out","w",stdout);
scanf("%d%d",&n,&wr);
for(i=1;i<=n;i++)
  {
  scanf("%d%d",&p1,&p2);
  a[p1]=a[p1]+p2;
  aux=max;
  if(i>1)
    {
    for(j=1;j<=aux;j++)
      {
      if(a[j]!=0)
	{
	a[j+p1]=a[j]+p2;
	if(j+p1>max)
	  max=j+p1;
	}
      }
    }
  if(p1>max)
    max=p1;
  }
min=10001;
for(i=wr;i<=max;i++)
  if(min>a[i] && a[i]!=0)
    min=a[i];
printf("%d",min);
return 0;
}