#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(pr[i]<pr[i+1]){swap(pr[i+1],pr[i]);
                      swap(gr[i+1],gr[i]);
                      srt=0;}
    }
      i=1;
      while(grmax>0)
      { prmax+=pr[i];grmax-=gr[i];i++;}
      //if(grmax<0)prmax-=pr[i];
      g<<prmax;
}