#include<cstdio>
using namespace std;
long n,d,k,i;
long a[1000001];
long c[1000001];
void read () {
	long i;
	scanf("%ld%ld%ld",&d,&n,&k);
	for (  i=1;i<=n;i++) 
		scanf("%ld",&a[i]);
}

long cautbin (long st , long dr) {
	long m,min2_rasengan=2000000000,i;
	i=dr;
	while (st<=dr && st<=i && dr<=i && m!=i) {
		m=(st+dr)/2;
		if (a[i]-a[m]>d)
			st=m+1;
		else
			if (m<=min2_rasengan && m!=i) {
				min2_rasengan=c[m];
				dr=m-1;
			}
	}
	return min2_rasengan;
}

void rez() {
	long i,rasengan,min=d,rasengan2,min_rasengan2,j;
	for (i=1;i<=n;i++) {
		rasengan=c[i-1]+1;
		min_rasengan2=cautbin (0,i);
		if (rasengan<min_rasengan2+k)
			c[i]=rasengan;
		else
			c[i]=min_rasengan2+k;
	}
	printf("%ld\n",c[n]);
}

int main () {
	
	freopen("zombie.in","r",stdin);
	freopen("zombie.out","w",stdout);
	
	read();
	rez();
	return 0;
}