#include<stdio.h>
#include<math.h>
main()
{
float a[1500][5],aux;
long i,j,w,k,l,n,m,sp,valid,x,s;
FILE *f,*g;
f=fopen("energii.in","r");
g=fopen("energii.out","w");
fscanf(f,"%ld%ld",&n,&w);
for(i=1;i<=n;i++)
 { fscanf(f,"%f%f",&a[i][1],&a[i][2]);
   a[i][3]=a[i][1]/a[i][2];
   x=1;
 }
i=1;
do{
   if(i<1)i=1;
   if(a[i][3]<a[i+1][3]){ aux=a[i][3];a[i][3]=a[i+1][3];a[i+1][3]=aux;
			  aux=a[i][2];a[i][2]=a[i+1][2];a[i+1][2]=aux;
			  aux=a[i][1];a[i][1]=a[i+1][1];a[i+1][1]=aux;
			  i-=2;
			 }
   i++;
   }while(i<n);
s=0;i=1;k=0;
do{
    s+=floor(a[i][2]);
    k+=floor(a[i][1]);
    i++;
   }while(k<w);
fprintf(g,"%ld",s);




fclose(f);
fclose(g);
return 0;
}