#include<stdio.h>
#include<math.h>
#include<iostream.h>
#include<fstream.h>
main()
{
double a[10000][10],aux;
long i,j,w,k,l,n,m,sp,valid,x,s;
fstream f("energii.in",ios::in);
fstream g("energii.out",ios::out);
f>>n>>w;
for(i=1;i<=n;i++)
 { f>>a[i][1];f>>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);
g<<s;




f.close();
g.close();
return 0;
}