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

void printVec(int *v, int n)
{
     int i;
     for ( i = 0; i<n; i++)
          printf("%.2d ",v[i]);
     printf("\n");
}

void merge(int *v,int *w, int p, int q, int r) {
	int i = p;
	int j = q + 1;
	
	int *tmp = (int*)malloc((r - p + 1) * sizeof(int));
	int *tmp2 = (int*)malloc((r-p+1)*sizeof(int));
	int k = 0;
	
	while ((i <= q) && (j <= r)) {
		if (v[i] > v[j]){
		     tmp2[k] = w[i];
			tmp[k++] = v[i++];
			} 
		else{
		     tmp2[k] = w[j];
			tmp[k++] = v[j++];
			}
	}
	
	while (i <= q){
	     tmp2[k] = w[i];
		tmp[k++] = v[i++];
	}
	
	while (j <= r){
	     tmp2[k] = w[j];
		tmp[k++] = v[j++];
	}
	
	memcpy(v + p, tmp, (r - p + 1) * sizeof(int));
	memcpy(w + p, tmp2, (r - p + 1) * sizeof(int));
	free(tmp);
	free(tmp2);
}


void mergeSort(int *h, int *w, int p, int r)
{
     if (p<r){
          int q = (p+r)/2;
          mergeSort(h,w,p,q);
          mergeSort(h,w,q+1,r);
          merge(h,w,p,q,r);
     }
}
int main()
{
     int N,H,U;
     FILE *f, *g;
     f = fopen("gutui.in","r");
     g = fopen("gutui.out","w");
     fscanf(f,"%d%d%d",&N,&H,&U);
     int h[N],w[N];
     int i,j;
     for ( i = 0; i<N; i++)
          fscanf(f,"%d %d\n",&h[i],&w[i]);
     /* printVec(h,N);
      printf("\n");
      printVec(w,N);*/
      mergeSort(h,w,0,N-1);
      /*for ( i = 0; i<N-1; i++)
          for ( j = i+1; j<N; j++)
               if (h[i]==h[j] && w[i]<w[j]){
                    int aux = w[i];
                    w[i] = w[j];
                    w[j] = aux;
               }*/
      printVec(h,N);
      printf("\n");
      printVec(w,N);
      int Gmax = 0;
      for ( i = 0; i<N; i++)
          if (h[i]<=H){
               Gmax+=w[i];
               for (j = i;j<N; j++)
                    h[j]+=U;
          }
      //printVec(h,N);
      fprintf(g,"%d\n",Gmax);
      fclose(f);
      fclose(g);
      return 0;
}