#include<fstream>
#define dim 1000007
using namespace std;
ifstream f("zombie.in");
ofstream g("zombie.out");
long long sol,n,d,k,i,j,x,a[dim];
int main (){
	
	f>>d>>n>>k;
	
	for(i=1;i<=n;i++)
		f>>a[i];
	
	for(i=1;i<=n;i++){
		x=a[i];
		j=i+1;
		while(a[j]<x+d)
			j++;
		j--;
		if(j-i>k)
			sol+=k;
		else
			sol+=j-i+1;
		i=j;
	}
	g<<sol<<"\n";
	return 0;
}