hole_num, length= list(map(int,input().split()))
hole_list = list(map(int,input().split()))
hole_list.sort()
now_tape = 0
count = 0
while len(hole_list)>0:
new_hole = hole_list.pop(0)
if new_hole+0.5 <= now_tape:
continue
now_tape = new_hole-0.5+length
count +=1
print(count)