#include<stdio.h>
using namespace std;
FILE*in=fopen("energii.in","r");
FILE*out=fopen("energii.out","w");
int g,w,i,a,b,s,j,m;
double max,e;
typedef struct generator
{
    int a;
    int b;
    double e;
};
generator v[1003];
int main()
{
    fscanf(in,"%d%d",&g,&w);
    for(i=0;i<g;i++)
            {
            fscanf(in,"%d%d",&v[i].a,&v[i].b);
            v[i].e=(double)v[i].a/v[i].b;
            }
    for(i=0;i<g;i++)
        for(j=i+1;j<g;j++)
            if(v[i].e<v[j].e)
                {
                v[1003]=v[i];
                v[i]=v[j];
                v[j]=v[1003];
                }

    for(i=0;i<=g;i++)
        if(s+v[i].a>=w)
            {
                fprintf(out,"%d",m+v[i].b);
                i=g+1;
            }
        else
            {
                s=s+v[i].a;
                m=m+v[i].b;
            }
fclose(in);
fclose(out);
return 0;
}