#include <iostream>
#include <fstream>
using namespace std;

FILE* fin = fopen("zombie.in", "r");
FILE* fout = fopen("zombie.out", "w");

typedef long long int64;

#define MAXN 1000100

int64 d, n, k;
int64 v[MAXN];

int main()
{
	fscanf (fin, "%lld %lld %lld\n", &d, &n, &k);
	
	int64 sol = 0;
	for (int i = 1, b; i <= n; ++i) {
		fscanf (fin, "%lld ", &v[i]);
	}
	
	int64 b = v[1];
	for (int i = 1; i <= n; ++i) {
		int j = i;
		while (v[j] - b < d && j <= n) {
			++j;	
		}
		
		if (j - i > k) {
			sol += k;	
		} else {
			sol += j - 1;	
		}
		
		b = v[j];
		i = j - 1;
	}
	
	fprintf(fout, "%lld\n", sol);
	
	fclose(fin);
	fclose(fout);
	return 0;
}