#include <fstream>
using namespace std;
ifstream fin("zombie.in");
ofstream fout("zombie.out");

int d, n, k, first, numbering = 1, cost;

void read_input() {
    fin >> d >> n >> k >> first;
    for (int i = 1; i < n; ++i) {
        int x;
        fin >> x;
        if (x - first + 1 < d)
            ++numbering;
        else {
            (numbering > k)? cost += k: cost += numbering;
            numbering = 1;
            first = x;
        }
    }
    (numbering > k)? cost += k: cost += numbering;
    fout << cost;
}

int main()
{
    read_input();
    return 0;
}