#include<fstream>
using namespace std;
ifstream in("zombie.in");
ofstream out("zombie.out");

const int nmax = 1000006;
int d, n, k, v[nmax], p1, rasp;

int main(){
	int player_unu=0;

	in>>d>>n>>k;
	for(int i = 1; i<=n; i++)
	{
		in>>v[i];
	}
	v[n + 1] = 2000000006;

	for(int i = 1; i<=n; i++)
	{
		while(v[p1 + 1] - v[i]<=d)
			p1++;

		if(p1 - i>=k)
		{
			rasp += k;
			i = p1;
		}
		else
		{
			rasp++;
		}
	}

	out<<rasp<<'\n';

	return player_unu;
}