#include <fstream>
#include <iostream>
#include <vector>
#include <algorithm>
#include <stdlib.h>
#define INF 100000
using namespace std;

int partition(int *a, int *b, int p, int r)
{
	int i, j, x, y;
	x = a[r];
	y = b[r];
	i = p - 1;
	for(j = p; j < r; j++)
		if((a[j] > x) || (a[j] == x && b[j] > y))
		{
			i++;
			swap(a[i], a[j]);
			swap(b[i], b[j]);
		}
	swap(a[i+1], a[r]);
	swap(b[i+1], b[r]);	
	return (i + 1);	
}	

void quicksort(int *a,int *b, int p, int r)
{
	if(p < r)
	{
		int q = partition(a, b, p, r);
		quicksort(a, b, p, q - 1);
		quicksort(a, b, q + 1, r);
	}
}		

int main()
{
	int n, h, u;	// nr. gutui, inaltime maxima, cu cat se ridica
	int nn, hh, ww;
	int i, j, min, poz, maxim = -INF;
	int *weight, *height, *NrGutui, *Sol, *renunt;
	
	ifstream in("gutui.in");		
	ofstream out("gutui.out");
	in >> nn;
	in >> h;
	in >> u;
	
	weight = (int *)malloc(nn * sizeof(int));
	height = (int *)malloc(nn * sizeof(int));
	renunt = (int *)malloc(nn * sizeof(int));
	n = 0;
	for(i = 0; i < nn; i++)
	{
		in >> hh;		in >> ww;	
		if(hh <= h)
		{
			height[n] = hh;
			weight[n] = ww;
			renunt[n] = 0;
			n++;
		}	
	}
	
	// sortat descrescator dupa inaltime
	quicksort(height, weight, 0, n - 1);
	
	Sol = (int *)malloc(n * sizeof(int));
	NrGutui = (int*)malloc(n * sizeof(int));
	

	Sol[0] = weight[0];
	NrGutui[0] = 1;
	
	for(i = 1; i < n; i++)
	{
		//	cout<<height[i] + NrGutui[i - 1] * u<<" ";
		if((height[i] + NrGutui[i - 1] * u) <= h)
		{
			Sol[i] = Sol[i - 1] + weight[i];
			NrGutui[i] = NrGutui[i - 1] + 1;
		}
		else
		{
			// Nu poti sa culegi gutuia i
			NrGutui[i] = NrGutui[i - 1];
			Sol[i] = Sol[i - 1];
			min = INF;
			poz = 0;
			
			// Incerci sa renunti la una culeasa, astfel incat daca ai renunta la ea
			// si ai culege gutuia i, ai avea un profit mai mare
			for(j = 0; j < i; j++)
				if((renunt[j] == 0) && (min > weight[j]))
				{
					min = weight[j];
					poz = j;
				}
				
			if(min < weight[i])
			{
				renunt[poz] = 1;
				Sol[i] = Sol[i - 1] - weight[poz] + weight[i];
			}
			else
				renunt[i] = 1;
		}
		//cout<<Sol[i]<<" "<<NrGutui[i]<<"\n" ;
	}	
				
	out<<Sol[n - 1];				
				
	in.close();
	out.close();
	return 0;
}