#include <fstream.h>
#include <iostream.h>
using namespace std;
  int main()
  { ifstream f("energii.in");
    ofstream gf("energii.out");
    short int g,w,i,c,e,s;
    float ef[1001],v[1001],u[1001],aux;
    f>>g;
    f>>w;
    for(i=1;i<=g;i++)
    {f>>v>>u;}
    f.close();
     for(i=1;i<=g;i++)
     {  ef=v/u;}
       do
       {
         c=1;
       for(i=1;i<=g-1;i++)
       { if (ef<ef[i+1])
           {aux=v;
        v=v[i+1];
        v[i+1]=aux;
        aux=u;
        u=u[i+1];
        u[i+1]=aux;
        aux=ef;
        ef=ef[i+1];
        ef[i+1]=aux;
        c=0;
        } } }
    while (c==0);
         s=0;
         i=1;
         e=0;
     do
       { e=e+v;
         s=s+u;
         i++; }
     while((i<=g) && (e<w));
     gf<<s;
         return 0;
      }