#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <algorithm>
#define MAXN 100000
#define DEBUG 0

#define PR(x) (x-1)/2
#define CH1(x) (x*2)+1
#define CH2(x) (x*2)+2

using namespace std;

vector<vector<int>> v;
int nrb = 0;

static inline int bracket(int x, int y, int z){
  return (x-z) / y;
}

int main(){
  int n, x, y;

  ifstream fin ("lupu.in");
  fin >> n >> x >> y;

  nrb = bracket(x, y, 0) + 1;
  v.resize(nrb);

  for(int i = 0; i < n; i ++){
    int d, l;
    fin >> d >> l;
    v[bracket(x, y, d)].push_back(l);
  }
  fin.close();

  for(int i = 0; i < nrb; i ++)
    sort(v[i].begin(), v[i].end());

  if(DEBUG){
    for(int i = 0; i < nrb; i ++){
      printf("%d: ", i);
      for(int j = 0; j < (int)v[i].size(); j ++){
        printf("%d ", v[i][j]);
      }
      printf("\n");
    }
    printf("\n");
  }

  priority_queue<int> hp;
  
  int sum = 0;
  for(int i = nrb - 1; i >= 0; i --){
    for(int j = 0; j < (int)v[i].size(); j ++)
      hp.push(v[i][j]);

    if(!hp.empty()){
      sum += hp.top();
      hp.pop();
    }
  }

  ofstream fout ("lupu.out");
  fout << sum << endl;
  fout.close();

  return 0;
}