#include <fstream>
#include <iostream>
#include <queue>

using namespace std;

ifstream f("lupu.in");
ofstream g("lupu.out");

vector< priority_queue<long> > C;

priority_queue<long> T;

int main()
{
    long N,X,L,D,A;
    unsigned c;

    f>>N>>X>>L;

    for(int i=0;i<N;i++)
    {
        f>>D>>A;
        if(D<=X)
        {
            c=D;
            while(C.size()<=c) C.push_back(T);
            C[c].push(A);
        }
    }

    long long sum=0;
    long k=0,Max=0,n=C.size()-1;

    for(int i=n;i>=0;i--)
    {
        k++;
        if(!C[i].empty() && k<=L)
        {
            if(C[i].top()>Max) Max=C[i].top();
        }
        if(k==L || i==0)
        {
            sum+=Max;
            Max=0;
            k=0;
        }

    }

    g<<sum;

    return 0;
}