#include<stdio.h>
int n,e,i,j;
int b[100],energ[100],c[100],cost[100];
int main(void)
{
	freopen("energii.in","r",stdin);
	freopen("energii.out","w",stdout);
	scanf("%d%d",&n,&e);
b[0]=1;

	for(i=1;i<=n;i++)
	{
		scanf("%d%d",&energ[i],&c[i]);
		for(j=e;j>=0;j--)
		{
			if(cost[j]||cost[j]+c[i]<cost[j+energ[i]])
			{
				cost[j+energ[i]]=cost[j]+c[i];
				b[j+energ[i]]=b[j]+1;
			}
			else
			{
				cost[energ[i]]=c[i];
				b[j]=1;
			}
		}
	}
	printf("%d\n",cost[e]);
	return 0;
}