#include <stdlib.h>
#include <stdio.h>

typedef struct {
  int h;
  int g;
}gutui;

int compare(const void *a, const void *b)
{
    gutui *aa = (gutui *)a;
    gutui *bb = (gutui *)b;
    return (bb->g -aa->g);
}
int max(gutui *a,int level,int n,int u)  //inaltimea de pe levelul curent careia ii corespunde greutatea max
{ 
    int max=0,i,j,aux=0;
  for(i=0;i<n;i++)
      if(a[i].h/u+1==level || a[i].h/u==level)
         if(a[i].g>max)
              max=a[i].g;
  for(i=0;i<n;i++)
      if(a[i].g==max)
        aux=a[i].h;
 return aux;
}
int retrieve(int test[],int index,int h_max,int u,gutui *a)
{  
            if(test[index]==0)
            {
                       test[index]=1;
                       return 1;
            }  
            if(test[index]==1) //daca am mai luat o gutuie de pe acest nivel
              for(index;index<=h_max/u;index++) 
                if(test[index]==0) //daca mai pot lua gutui
            {
                       test[index]=1;
                       return 1;
            } 
             
   return 0;
}
int main()
{
    FILE *fis=fopen("gutui.in","r");
    FILE *fis_out=fopen("gutui.out","w");
    int n,h_max,u,i,j,aux=0,greutate=0;
    fscanf(fis,"%i",&n);
    gutui a[n];
    fscanf(fis,"%i",&h_max);
    fscanf(fis,"%i",&u);
    for(i = 0; i < n; i++)
        fscanf(fis, "%i %i", &a[i].h,&a[i].g);
      
   qsort(a,n,sizeof(gutui),compare);    //gutui sortate descrescator dupa greutate
    int test[h_max/u+1];
    for(i=0;i<=h_max/u;i++)
            test[i]=0; 
 for(i=0;i<n;i++)
  {  
  if(a[i].h%u==h_max%u)
     { if(retrieve(test,a[i].h/u,h_max,u,a)==1)
           greutate+=a[i].g;
       }
    else          
       if(retrieve(test,a[i].h/u+1,h_max,u,a)==1)
              greutate+=a[i].g;
    }
 printf("Greutatea maxima este : %i",greutate);
  fprintf(fis_out,"%i",greutate);
 //getch();
   return 0; 
}