#include <fstream>
#include <vector>
#include <algorithm>
#include <iostream>

std::ifstream in("tribute.in");
std::ofstream out("tribute.out");

int getRez(std::vector<int> & vm,int dist){
    int rez=0;
    std::sort(vm.begin(),vm.end());
    int dr=vm.size()-1;
    int st=0;
    for(;vm[dr]-vm[st]>dist;dr--,st++)
        rez+=vm[dr]-vm[st]-dist;
    return rez;
}

std::vector<int>v1,v2;

int main(){
    int n,a,b;
    in>>n>>a>>b;
    for(int i=0,x,y;i<n;i++)
        in>>x>>y,v1.push_back(x),v2.push_back(y);
    out<<getRez(v1,a)+getRez(v2,b);
    return 0;
}