#include <fstream>

using namespace std;

ifstream in;
ofstream out;

int v[1000010];

int main()
{
    int D,N,K;

    in.open("zombie.in");
    in>>D>>N>>K;
    for(int i=1;i<=N;++i) in>>v[i];
    in.close();

    int sol=0;

    out.open("zombie.out");
    if(K>D) out<<N<<'\n';
    else
    {

    for(int i=1;i<=N;)
    {
        int j=i+K-1;
        int ok=0;
        while(v[j]-v[i]<=D&&j<=N) ++j,ok=1;
        if(ok&&v[j]-v[i]>D) --j;
        if(v[j]-v[i]<=D)
        {
            i=j+1;
            sol+=K;
        }
        else
        {
            ++i;
            ++sol;
        }
    }

    out<<sol<<'\n';

    }

    out.close();

    return 0;
}