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

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

int compare (const void * a, const void * b)
{
  return ( *(int*)b - *(int*)a );
}

void Minim(int* v,int min,int poz,int dim){
     int i;
     for(i=0;i<dim;i++)
      if(v[i]<=min){
         min=v[i];
         poz=i;
      }
     
}

int main(){
 FILE* fisierin=fopen("gutui.in","r");
 FILE* fisierout=fopen("gutui.out","w");
 int n,h,u,i;
 GUT* vec;
 int* aux;  
  
 fscanf(fisierin,"%d ",&n); 
 printf("%d \n",n); 
 fscanf(fisierin,"%d ",&h); 
 printf("%d \n",h);
 fscanf(fisierin,"%d ",&u); 
 printf("%d \n",u);
 
 
 vec=(GUT*)malloc(n*sizeof(GUT));
 aux=(int*)malloc(n*sizeof(int));
 
 for(i=0;i<n;i++){
  fscanf(fisierin,"%d",&vec[i].h);
  fscanf(fisierin,"%d",&vec[i].g);
  
   printf("%d  %d \n",vec[i].h,vec[i].g);
}

qsort (vec, n, sizeof(GUT), compare);

printf("////////////////////////\n");

for(i=0;i<n;i++){
   printf("%d  %d \n",vec[i].h,vec[i].g);
   aux[i]=0;
}
printf("////////////////////////\n");

aux[0]=vec[0].g;
int dim=1;
int min;
int poz;
for(i=1;i<n;i++){
                 min=50000;
                 poz=0;
     if(vec[i].h<=h){
       aux[dim]=vec[i].g;
       h=h-u;
       dim++;
     }
     
     else{Minim(aux,min,poz,dim);
          if(vec[i].g<min)
           aux[poz]=vec[i].g;
          
          }
          }
int cant_max=0;
for(i=0;i<dim;i++)
 cant_max=cant_max+aux[i];

printf("%d ",cant_max);
fprintf(fisierout,"%d \n",cant_max);
          


 fclose(fisierin);
 fclose(fisierout);
 getchar();
 return 0; 
   
}