#include <fstream>

using namespace std;
ifstream f("energii.in");
ofstream g("energii.out");
int n,w,eg[1002],cg[1002],i,k,e,c,aux;
int main()
{
    f>>n>>w;
    for(i=1;i<=n;i++)
    {
        f>>eg[i]>>cg[i];e+=eg[i];c+=cg[i];
    }
    do{
        k=0;
        for(i=1;i<n;i++)
        {
            if(cg[i]>cg[i+1])
            {aux=cg[i];cg[i]=cg[i+1];cg[i+1]=aux;
            aux=eg[i];eg[i]=eg[i+1];eg[i+1]=aux;k=1;}
        }
    }while(k);
    for(i=n;i>=1;i--)
    {
        if(e-eg[i]>=w)
        {c-=cg[i];e-=eg[i];}
    }
    g<<c;
    return 0;
}