#include <fstream>
using namespace std;

ifstream f("zombie.in");
ofstream g("zombie.out");

int d,n,k,sol;
int a[1000100];
int main()
{
    f>>d>>n>>k;
    for(int i=1;i<=n;++i)
        f>>a[i];

    for(int i=1;i<=n;)
    {
        int nr=i;
        ++i;
        while(a[i]<=a[nr]+d-1) ++i;
        if(i-nr>=k) sol+=k;
        else sol+=(i-nr);
    }

    g<<sol<<'\n';
    g.close();
    return 0;
}