#include <fstream>
using namespace std;

ifstream fin("zombie.in");
ofstream fout("zombie.out");

#define lmax 2000011

int D,N,K,A[lmax];
int co;

int main()
{
	fin>>D>>N>>K;
	for (int i=1; i<=N; ++i)
		fin>>A[i];	
	
	int i=1;
	for (;i<=N;)
		if (A[i+K]-A[i]>D) 
		{
			++i;
			++co;
		}
		else
		{
			int poz=i;
			for (;A[i+K]-A[poz]<=D && i<=N;++i); 
			co+=K;
		}

	fout<<co<<'\n';
	fin.close();
	fout.close();
	return 0;
}