#include <stdio.h>
02.#include <stdlib.h>
03.#include <string.h>
04.#define in "gutui.in"
05.#define out "gutui.out"
06. 
07.typedef struct
08.        {
09.        int h;
10.        int g;     
11.        int coef;
12.        }pom;
13.int compare2(const void *a,const void *b)
14.    {
15.    pom *x,*y;
16.    x=(pom*)a;
17.    y=(pom*)b;
18.    return -x->g + y->g              ;
19.    }
20. 
21.int compare(const void* a,const void* b)
22.    {
23.    pom *x,*y;
24.    x=(pom*)a;
25.    y=(pom*)b;
26.    if (x->coef != y->coef)
27.       return x->coef-y->coef;
28.    else
29.        return -x->g+y->g;             
30.    }
31. 
32.int main()
33.    {
34.    int j,n,i,max_height,up_height,sum=0,nr=0,*frei;
35.    pom *gutui;
36.    freopen(in,"r",stdin);
37.    freopen(out,"w",stdout);
38.    scanf("%d %d %d",&n,&max_height,&up_height);
39.    gutui=(pom*)malloc(n*sizeof(pom));
40.    for (i = 0; i < n; ++i)
41.        {
42.        scanf("%d %d",&gutui[i].h,&gutui[i].g);
43.        gutui[i].coef=(max_height-gutui[i].h)/up_height+1;
44.        if (nr < gutui[i].coef)
45.           nr = gutui[i].coef;
46.        if( gutui[i].h > max_height )
47.            {
48.            i--;
49.            n--;          
50.            }
51.        }
52.    qsort(gutui,n,sizeof(pom),compare2);
53.    frei = (int*)malloc(nr*sizeof(int));
54.    memset(frei,0,(nr+1)*sizeof(int));
55.    for (i = 0; i < nr; ++i)
56.        {
57.         
58.        for ( j = gutui[i].coef ; j > 0; j--)
59.            {
60.            //printf("%d %d\n",j,frei[j]);
61.            if (frei[j] == 0)
62.               {
63.              // printf("me:%d %d %d \n",gutui[i].h,gutui[i].g,gutui[i].coef);  
64.               sum += gutui[i].g;
65.               frei[j] = 1;
66.               break;       
67.               }
68.            }   
69.        if (j == 0 && nr < n)
70.           nr++;
71.        }
72.    printf("%d\n",sum);
73. 
74.    return 0;     
75.    }