#include<stdio.h>
#include<ctype.h>
#include<fstream>
using namespace std;

ifstream f("zombie.in");

#define MaxN 1000100

int N,D,K,A[MaxN];
int B[MaxN];

void citire(void)
{
	f >> D >> N >> K;
	for(int i=1;i<=N;i++)
		f >> A[i];
	
}

int binary_search(int li,int ls,int a)
{
	if(li <= ls)
		if(A[(li+ls)/2] == a)
			return (li+ls)/2-1;
		else if(A[(li+ls)/2] > a)
			return binary_search(li,(li+ls)/2-1,a);
		else
			return binary_search((li+ls)/2+1,ls,a);
	return ls;
}

void zombie(void)
{
	int c;
	for(int i=1;i<=N;i++)
	{
		B[i] = B[i-1]+1;
		c = binary_search(1,i-1,A[i]-D);
		if(B[i] > B[c]+K)
			B[i] = B[c] + K;
	}
}

int main()
{
	FILE *g = fopen("zombie.out","w");
	
	citire();
	zombie();
	fprintf(g,"%d ",B[N]);
	
	fclose(g);
	return 0;
}