# include <fstream>
using namespace std;

const char *FIN = "zombie.in", *FOU = "zombie.out";

ifstream f (FIN);
ofstream g (FOU);

int D, N, K, V[1000105];

int main (void) {
    f >> D >> N >> K;
    for (int i = 1; i <= N; ++i)
        f >> V[i];
    int sol = 0;
    for (int i = 1; i <= N; ) {
        int z = i++;
        for (; V[i] <= V[z] + D - 1; ++i);
        sol += (i - z >= K ? K : i - z);
    }
    g << sol;
}