#include<string.h>
#include<fstream>
using namespace std;
int main()
{
    fstream f,g;
    f.open("rucsac.in",ios::in);
    g.open("rucsac.out",ios::out);
    int n,m,p=0,s=0,a[5000],b[5000],aux,i,j;
    f>>n>>m;
    for(i=1; i<=n; i++)
    f>>a[i]>>b[i];
    for(i=1; i<=n; i++)
    for(j=i+1; j<=n; j++)
    if(b[i]<b[j])
    {
        aux=b[i];
        b[i]=b[j];
        b[j]=aux;
        aux=a[i];
        a[i]=a[j];
        a[j]=aux;
    }
    for(i=1; i<=n && s+a[i]<=m; i++)
    {
            p=p+b[i];
            s=s+a[i];


    }
    g<<p;
}