Program zombie;
 var d,n,k,sum,i,j,cap,s:longint;
     fi,fo:text;
function min(a,b:longint):longint;
begin
 if a<b then min:=a
          else min:=b;
end;
begin
 assign(fi,'zombie.in');
  assign(fo,'zombie.out');
 reset(fi); rewrite(fo);
 readln(fi,d,n,k); read(fi,cap); j:=1;
 for i:=1 to n-1 do begin
                     read(fi,s);
                     if (s-cap>=n) or (i=n-1) then begin
                                          sum:=sum+min(j,k);
                                           cap:=s;
                                            j:=1;
                                           end
                      else inc(j);
                      end;
 write(fo,sum);
close(fo);
end.