//Voinea Maria Anemona 321CA
//--------Tema 1 PA---------

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

int main()
{
	FILE *in, *out;
	int i, j, c, N, H, U, *h, *g, G=0, gutui=0, etape=0, curent = 0;
	char s[50], *ordine;
	in = fopen("gutui.in", "r");
	out = fopen("gutui.out", "w");
	
	fgets(s, 50, in);
	sscanf(s, "%d%d%d", &N, &H, &U);
	//printf("%d %d %d\n", N, H, U);
	
	h = (int*)malloc(N*sizeof(int));
	g = (int*)malloc(N*sizeof(int));

	for(i=0; i<N; i++)
	{
		fgets(s, 50, in);
		sscanf(s, "%d%d", h+i, g+i);
	}
	fclose(in);
	
	//Calculul numarului maxim de gutui culese (numarul de etape ale culesului)
	for(i=0; i<N; i++)
	{
			if( H-h[i] > 0 && (H-h[i]) / U + 1 > etape )
				etape = (H-h[i]) / U + 1;
	}
	//printf("Etape: %d\n", etape);
	if(!etape)
	{
		fprintf(out, "0"); //nu se poate culege nimic
		return 0;
	}
	
	//Sortare dupa greutate
	for(i=0; i<N-1; i++)
		for(j=i+1; j<N; j++)
			if(g[i] < g[j])
			{
				c = g[i];
				g[i] = g[j];
				g[j] = c;
				c = h[i];
				h[i] = h[j];
				h[j] = c;	
			}

	ordine = (char*)malloc(etape*sizeof(char));
	memset(ordine, -1, N);

	while(curent < N && gutui < etape)
	{
		if(H - h[curent] >= 0); //etapa maxima la care se poate culege gutuia curenta
		{
			i = (H - h[curent]) / U;
			//Daca a mai fost culeasa o gutuie in etapa i, incearca etapa anterioara
			while( i >= 0 && ordine[i] > 0)
				i--;
			if(i >= 0) //daca s-a putut alege gutuia
			{
				G += g[curent];
				ordine[i] = 1;
				gutui++;
				printf("Culeasa cea de inaltime %d si de greutate %d\n", h[curent], g[curent]);
			}
		}
		curent++;
	}

	fprintf(out, "%d", G);
	fclose(out);
	
	return 0;
}