#include<fstream>
#define MAX 1000002
using namespace std;
int v[MAX],n,d,k,c[MAX],rez;
void solve();
int main()
{
	ifstream fin("zombie.in");
	ofstream fout("zombie.out");
	fin>>d>>n>>k;
	int i;
	for(i=1;i<=n;i++)
		fin>>v[i];
	solve();
	fout<<rez<<endl;
	return 0;
}
void solve()
{
	int i,sp=1;
	for(i=1;i<=n;i++)
		if(v[i]-v[sp]>d)
		{
			c[sp]=i-sp;
			while(v[i]-v[sp]>d)
			{
				c[sp]=i-sp;
				sp++;
			}
		}
	for(;sp<=n;sp++)
		c[sp]=n-sp+1;
	for(i=1;i<=n;i++)
		if(c[i]>k)
			rez+=k,i+=c[i]-1;
		else
			rez++;
}