#include<stdio.h>
#include<queue>
#include<algorithm>
using namespace std;

struct pu {
	int d,p;
};

priority_queue<int> h;
pu x[100001];
int n,xx,l;

bool cmp(pu a,pu b) {
	return a.d<b.d;
}

int main() {
	long long i,sum=0,a1=0,pen=0;
	freopen("lupu.in","r",stdin);
	freopen("lupu.out","w",stdout);
	scanf("%d%d%d",&n,&xx,&l);
	for(i=1;i<=n;++i) {
		scanf("%d%d",&x[i].d,&x[i].p);
		x[i].d=xx/(x[i].d+l);
		sum+=x[i].p;
	}
	sort(&x[1],&x[n+1],cmp);
	for(i=1;i<=n;++i) {
		if(x[i].d>=a1) {
			h.push(-x[i].p);
			a1++;
		}
		else {
			if(!h.empty() && x[i].p>=-h.top()) {
				pen=pen-(long long)h.top();
				h.pop();
				h.push(-x[i].p);
			}
			else {
				pen=pen+(long long)x[i].p;
			}
		}
	}
	printf("%lld",sum-pen);
	return 0;
}