#include<stdio.h>
FILE *f=fopen("energii.in","r"),
     *g=fopen("energii.out","w");
long double a[1300],b[1300][3];
int i,n,e,j;
long double x,y;
int main()
{ fscanf(f,"%d",&n);
  fscanf(f,"%d",&e);
  for(i=1;i<=n;++i){ fscanf(f,"%LE %LE",&b[i][1],&b[i][2]);
		     a[i]=b[i][1]/b[i][2];
		   }
  for(i=1;i<=n;++i) for(j=i+1;j<=n;++j) if(a[i]<a[j]) { x=a[i],a[i]=a[j],a[j]=x;
							x=b[i][1];b[i][1]=b[j][1];b[j][1]=x;
							x=b[i][2];b[i][2]=b[j][2];b[j][2]=x;
						      }
  x=0;y=0;i=0;
  while(x<e) x+=b[++i][1],y+=b[i][2];
  fprintf(g,"%d\n",int(y));
  fclose(f);
  fclose(g);
  return 0;
}