#include <fstream>
#define VAL 1000005

using namespace std;

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

int D, N, K, dp;
int z, i, j, prec;
int v[VAL];

int main ()
{
    fin >> D >> N >> K;
    for (i=1; i<=N; i++)
      fin >> v[i];
    prec=1;
    while (prec<=N)
    {
        z=0;
        j=prec;
        while (j<=N+1 && v[j]<=v[prec]+D-2)
        {
            j++;
            z++;
        }
        prec=j;
        dp+=min(z, K);
    }
    fout << dp << '\n';
    fin.close();
    fout.close();
    return 0;
}