#include<iostream>
#include<fstream>

using namespace std;

ifstream f("peste.in");
ofstream g("peste.out");
int p[50001],t[50001],k,n;

int main()
{
   char flag[50001];
   int n,k,ttotal,aux1,aux2,i;
   f>>n>>k>>ttotal;
  for (i=1 ; i<=n ;i++) 
  {f>>aux1>>aux2;
  if (aux2<=ttotal) {p[i]=aux1;t[i]=aux2;}
  else i--;}
 double sol=0;
 for(i=1;i<=n;i++) flag[i]=0;
   for(int y=1;y<=k;y++)
   {
                    int max1=0,max2=0,poz;
                    for(i=1;i<=n;i++)
                    if (flag[i]==0)
                    if (t[i]>max2) max2=t[i];
                    for(i=1;i<=n;i++)
                    {if (t[i]==max2) 
                    if (flag[i]==0)
                    if (p[i]>max1){max1=p[i];poz=i;}}
                    flag[poz]=1;
                    sol+=p[poz];
                    }
  g<<sol;
      
      f.close();
    g.close();
    return 0;
    }