#include<fstream>
#include<queue>
#include<algorithm>
using namespace std;
ifstream f("lupu.in");
ofstream g("lupu.out");
priority_queue<int> q;
pair<int,int>a[100005];
int n,x,l,i,lim=1;
long long int suma;
int main()
{
    f>>n>>x>>l;
    for(i=1;i<=n;i++)
        f>>a[i].first>>a[i].second;
    sort(a+1,a+n+1);
    for(i=x%l;i<=x;i+=l){
        while(lim<=n&&a[lim].first<=i){
            q.push(a[lim].second);
            lim++;
           }
        if(!q.empty()){
            suma+=q.top();
            q.pop();
         }
    }
    g<<suma;
}