#include<stdio.h>
using namespace std;
int main()
{
    FILE *q, *sf,*w;
    q=fopen("zombie.in","r");
    sf=fopen("zombie.in","r");
    w=fopen("zombie.out","w");
    int poz,zsfarsit,zinceput,d,n,k,costS=0,luate=0,ps=0,pozi=1;
    bool pending=false;
    fscanf(q,"%d%d%d",&d,&n,&k);
    if(k==d)
    {
        fprintf(w,"%d",n);
        return 0;
    }
    poz=1;
    fscanf(sf,"%d%d%d%d",&d,&n,&k,&zsfarsit);
    fscanf(q,"%d",&zinceput);
    while(poz<=n)
    {
        if(zsfarsit-zinceput+1<d)
         {if(poz-pozi+1>k)
        {
            pending=true;
            ps=poz;
        }}
        else{
          if(pending)
          {
              luate=luate+ps-pozi+1;
              costS=costS+k;
              pending=false;
              pozi=poz;
              zinceput=zsfarsit;
              q=sf;
          }
          else{
          fscanf(q,"%d",&zinceput);
          pozi++;}
          }
        poz++;
        if(poz<=n){
        fscanf(sf,"%d",&zsfarsit);
        }
    }
    if(pending)
          {
              luate=luate+ps-pozi+1;
              costS=costS+k;
              pending=false;
          }
    fprintf(w,"%d",(costS+n-luate));
    return 0;
}