# -*- coding: utf-8 -*-

import bisect

import heapq

import math

import random

from collections import Counter, defaultdict, deque

from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal

from functools import lru_cache, reduce

from itertools import combinations, combinations_with_replacement, product, permutations

from operator import add, mul, sub





import sys

# sys.setrecursionlimit(10**6)

# buff_readline = sys.stdin.buffer.readline

buff_readline = sys.stdin.readline

readline = sys.stdin.readline



INF = 2**62-1





def read_int():

    return int(buff_readline())





def read_int_n():

    return list(map(int, buff_readline().split()))





def read_float():

    return float(buff_readline())





def read_float_n():

    return list(map(float, buff_readline().split()))





def read_str():

    return readline().strip()





def read_str_n():

    return readline().strip().split()



def error_print(*args):

    print(*args, file=sys.stderr)





def mt(f):

    import time



    def wrap(*args, **kwargs):

        s = time.time()

        ret = f(*args, **kwargs)

        e = time.time()



        error_print(e - s, 'sec')

        return ret



    return wrap





@mt

def slv(L, R, D):

    ans = 0

    for i in range(L, R+1):

        if i % D == 0:

            ans += 1

    return ans





def main():

    L, R, D = read_int_n()

    print(slv(L, R, D))





if __name__ == '__main__':

    main()

# -*- coding: utf-8 -*-

import bisect

import heapq

import math

import random

from collections import Counter, defaultdict, deque

from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal

from functools import lru_cache, reduce

from itertools import combinations, combinations_with_replacement, product, permutations

from operator import add, mul, sub





import sys

# sys.setrecursionlimit(10**6)

# buff_readline = sys.stdin.buffer.readline

buff_readline = sys.stdin.readline

readline = sys.stdin.readline



INF = 2**62-1





def read_int():

    return int(buff_readline())





def read_int_n():

    return list(map(int, buff_readline().split()))





def read_float():

    return float(buff_readline())





def read_float_n():

    return list(map(float, buff_readline().split()))





def read_str():

    return readline().strip()





def read_str_n():

    return readline().strip().split()



def error_print(*args):

    print(*args, file=sys.stderr)





def mt(f):

    import time



    def wrap(*args, **kwargs):

        s = time.time()

        ret = f(*args, **kwargs)

        e = time.time()



        error_print(e - s, 'sec')

        return ret



    return wrap





@mt

def slv(L, R, D):

    return R // D - (L-1) // D





def main():

    L, R, D = read_int_n()

    print(slv(L, R, D))





if __name__ == '__main__':

    main()

# -*- coding: utf-8 -*-
import bisect
import heapq
import math
import random
from collections import Counter, defaultdict, deque
from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
from functools import lru_cache, reduce
from itertools import combinations, combinations_with_replacement, product, permutations
from operator import add, mul, sub
import sys

# sys.setrecursionlimit(10**6)
# buff_readline = sys.stdin.buffer.readline
buff_readline = sys.stdin.readline
readline = sys.stdin.readline
INF = 2**62 - 1


def read_int():
    return int(buff_readline())


def read_int_n():
    return list(map(int, buff_readline().split()))


def read_float():
    return float(buff_readline())


def read_float_n():
    return list(map(float, buff_readline().split()))


def read_str():
    return readline().strip()


def read_str_n():
    return readline().strip().split()


def error_print(*args):
    print(*args, file=sys.stderr)


def mt(f):
    import time

    def wrap(*args, **kwargs):
        s = time.time()
        ret = f(*args, **kwargs)
        e = time.time()
        error_print(e - s, "sec")
        return ret

    return wrap


@mt
def slv(L, R, D):
    ans = 0
    for i in range(L, R + 1):
        if i % D == 0:
            ans += 1
    return ans


def main():
    L, R, D = read_int_n()
    print(slv(L, R, D))


if __name__ == "__main__":
    main()

# -*- coding: utf-8 -*-
import bisect
import heapq
import math
import random
from collections import Counter, defaultdict, deque
from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
from functools import lru_cache, reduce
from itertools import combinations, combinations_with_replacement, product, permutations
from operator import add, mul, sub
import sys

# sys.setrecursionlimit(10**6)
# buff_readline = sys.stdin.buffer.readline
buff_readline = sys.stdin.readline
readline = sys.stdin.readline
INF = 2**62 - 1


def read_int():
    return int(buff_readline())


def read_int_n():
    return list(map(int, buff_readline().split()))


def read_float():
    return float(buff_readline())


def read_float_n():
    return list(map(float, buff_readline().split()))


def read_str():
    return readline().strip()


def read_str_n():
    return readline().strip().split()


def error_print(*args):
    print(*args, file=sys.stderr)


def mt(f):
    import time

    def wrap(*args, **kwargs):
        s = time.time()
        ret = f(*args, **kwargs)
        e = time.time()
        error_print(e - s, "sec")
        return ret

    return wrap


@mt
def slv(L, R, D):
    return R // D - (L - 1) // D


def main():
    L, R, D = read_int_n()
    print(slv(L, R, D))


if __name__ == "__main__":
    main()

-    ans = 0 -    for i in range(L, R + 1): -        if i % D == 0: -            ans += 1 -    return ans +    return R // D - (L - 1) // D