How many multiples of d are there among the integers between L and R (inclusive)?
def multiples(l,r,d):
  
  c = 0
  if d == 1:
    return r-l+1
  for i in range(l,r+1):
    if i%d==0:
      c += 1
    
  return c


if __name__ == '__main__':

  lrd = input().split()
  l = int(lrd[0])
  r = int(lrd[1])
  d = int(lrd[2])
  result = multiples(l,r,d)

def multiples(l,r,d):
  
    c = 0
    if d == 0:
      return 0
    if d==1:
        return r-l+1
    i = l
    while i<=r:
        
        if i%d==0:
            c += 1
            i += d
            continue

        i += 1
        
    return c


if __name__ == '__main__':

    lrd = input().split()
    
    l = int(lrd[0])
    r = int(lrd[1])
    d = int(lrd[2])

    result = multiples(l,r,d)
    print(result)