# include <fstream>
# include <algorithm>
using namespace std;
int a[1000005],n,d,k,sol;
int main()
{
	ifstream f("zombie.in");
	ofstream g("zombie.out");
	f>>d>>n>>k;
	for(int i=1;i<=n;++i)
		f>>a[i];
	int i=1,nr=0;
	while(i<=n)
	{
		nr=i;
		i++;
		while(a[i]<=a[nr]+d-1)
			i ++;
		if(i-nr>=k)
			sol=sol+k;
		else
			sol=sol+i-nr;
	}
	g<<sol;
}