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

struct oaie
{
    int poz,lana;
};

oaie v[100001];

bool cmp(oaie a,oaie b)
{
    if(a.poz==b.poz)
        return a.lana>b.lana;
    return a.poz>b.poz;
}
void scrie(int n)
{
    for(int i=1;i<=n;i++)
        printf("%d %d\n",v[i].poz,v[i].lana);
}
int main()
{

    freopen("lupu.in","r",stdin);
    freopen("lupu.out","w",stdout);
    int n,max,lung,i;
    long long sumMax=0;
    scanf("%d%d%d",&n,&max,&lung);
    for(i=1;i<=n;i++)
    {
        scanf("%d%d",&v[i].poz,&v[i].lana);
    }
    sort(v+1,v+n+1,cmp);//OK
    //scrie(n);
    int dist=0;
    int minHeap;
    for(i=1;i<=n;i++)
    {
        if(v[i].poz + dist <= max)
        {
            q.push(-v[i].lana);
            dist += lung;
            sumMax+=v[i].lana;
            continue;
        }
        if(q.size()!=0)
        {
            minHeap=-q.top();

            if(minHeap<v[i].lana)
            {
                q.pop();
                sumMax -= minHeap;
                q.push(-v[i].lana);
                sumMax += v[i].lana;
            }

        }
    }
    printf("%lld\n",sumMax);
    return 0;

}