#include <fstream>

using namespace std;

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

int N, D, K;
int x, xnow, nr;
int sol;

int main()
{
    fin >> D >> N >> K;

    fin >> x;
    xnow = x;
    for (int i = 1; i <= N; ++i)
    {
        nr = 0;
        while (x - xnow + 1 <= D && i <= N)
        {
            ++nr;
            ++i;
            fin >> x;
        }
        --i;
        xnow = x;

        sol += min(nr, K);
    }

    fout << sol << '\n';

    fin.close();
    fout.close();
    return 0;
}