#include <fstream>
#include <algorithm>

using namespace std;

const char InFile[]="tribute.in";
const char OutFile[]="tribute.out";
const int MaxN=50111;

ifstream fin(InFile);
ofstream fout(OutFile);

int n,dx,dy,x,y,vx[MaxN],vy[MaxN],sol;

int main()
{
	fin>>n>>dx>>dy;++dx;++dy;
	for(register int i=1;i<=n;++i)
	{
		fin>>vx[i]>>vy[i];
	}
	fin.close();

	sort(vx+1,vx+1+n);
	sort(vy+1,vy+1+n);

	int st=1;
	int sf=n;
	while(st<=sf)
	{
		int k=vx[sf]-vx[st]+1-dx;
		if(k>0)
		{
			sol+=k;
		}

		k=vy[sf]-vy[st]+1-dy;
		if(k>0)
		{
			sol+=k;
		}
		++st;
		--sf;
	}

	fout<<sol;
	fout.close();
	return 0;
}