#include <iostream>
#include <fstream>
using namespace std;
ifstream f("rucsac.in");
ofstream g("rucsac.out");
int nr,i,grmax,gr[5005],pr[5005],prmax;
bool srt=0;
int main()
{  f>>nr>>grmax;
   for(i=1;i<=nr;i++)
    f>>gr[i]>>pr[i];
    while(srt==0)
    {srt=1;
    for(i=1;i<nr;i++)
    if(gr[i]>gr[i+1]){swap(pr[i+1],pr[i]);
                      swap(gr[i+1],gr[i]);
                      srt=0;}
    }
    //for(i=1;i<=nr;i++)
    //cout<<gr[i]<<" "<<pr[i]<<'\n';
      for(i=1;i<=nr;i++)
      {prmax+=pr[i];
       grmax-=gr[i];
        if(grmax<=0){prmax-=pr[i];break;}
        }
       cout<<prmax;
}