#include<fstream.h>
int n,e,i,G[1001],C[1001],A[1001],j,min,s[1001];
ifstream f("energii.in");
ofstream g("enrgii.out");
int main (){
		f>>n>>e;
		for(i=1;i<=n;i++)
			f>>G[i]>>C[i];
		A[0]=1;min=20000000;
		for(i=1;i<=n;i++)
			for(j=e;j>=0;j--)
				if(A[j]&&j+G[i]<=e){
					A[j+G[i]]=1;
					s[j+G[i]]=C[j+G[i]]+s[j+G[i]];
					if(C[A[j]+G[i]]<min)
						min=C[A[j]+G[i]];
			}
					
	g<<min;
	
	
	
	
	return 0;
}