#include <fstream>
using namespace std;

ifstream f("zombie.in");
ofstream g("zombie.out");

int d, n, k, sol;
int a[1000100];
int main()
{
    f >> d >> n >> k;
    for (int i = 1; i <= n; ++i)
        f >> a[i];

    for (int i = 1; i <= n; )
    {
        int nr = i;
        ++i;
        while (a[i] <= a[nr] + d - 1) ++i;
        if (i - nr >= k) sol += k;
        else sol += (i - nr);
    }

    g << sol << '\n';
    g.close();
    return 0;
}