#include <bits/stdc++.h>

using namespace std;

ifstream fin("zombie.in");
ofstream fout("zombie.out");

const int NMAX = 1000005;
int a[NMAX];

int main()
{
    int d,n,k;
    fin >> d >> n >> k;
    for(int i=1;i<=n;i++) fin >> a[i];
    int i=1,rasp=0;
    while(i<=n)
    {
        int j=i+1;
        while(j<=n and a[j]-a[i]<d) j++;
        if(j-i>k) rasp+=k;
        else rasp+=(j-i);
        i=j;
    }
    fout << rasp;
    return 0;
}