#include <fstream>
#include <algorithm>
#define MAX_N 1000005
using namespace std;

int v[MAX_N],n,d,k;
void citire();

int main()
{
    int ct=0,cakra=0;
    v[1]=99999999;
    citire();

    for(int i=1;i<=n;++i)
    {
        for(;i<=n&&v[i]-v[i-1]<d;++i)
            ++ct;
        cakra+=min(ct,k);
    }


    ofstream fout("zombie.out");
    fout<<cakra;
    fout.close();

    return 0;
}

void citire()
{

    ifstream fin("zombie.in");
    fin>>d>>n>>k;

    for(int i=1;i<=n;++i)
    {
        fin>>v[i];
    }
    fin.close();
}