import sys

read = sys.stdin.read

readlines = sys.stdin.readlines

from math import ceil

from numba import njit

def main():

    n = int(eval(input()))

    @njit

    def s(n):

        res = 0

        for i1 in range(1, n + 1):

            for i2 in range(1, n + 1):

                if i1 * i2 >= n:

                    break

                else:

                    res += 1

        return res

    r = s(n)

    print(r)



if __name__ == '__main__':

    main()

import sys

read = sys.stdin.read

readlines = sys.stdin.readlines

def main():

    n = int(eval(input()))

    r = 0

    for i1 in range(1, n+1):

        for i2 in range(1, n+1):

            if i1 * i2 >= n:

                break

            else:

                r += 1

    print(r)



if __name__ == '__main__':

    main()

import sys

read = sys.stdin.read
readlines = sys.stdin.readlines
from math import ceil
from numba import njit


def main():
    n = int(eval(input()))

    @njit
    def s(n):
        res = 0
        for i1 in range(1, n + 1):
            for i2 in range(1, n + 1):
                if i1 * i2 >= n:
                    break
                else:
                    res += 1
        return res

    r = s(n)
    print(r)


if __name__ == "__main__":
    main()

import sys

read = sys.stdin.read
readlines = sys.stdin.readlines


def main():
    n = int(eval(input()))
    r = 0
    for i1 in range(1, n + 1):
        for i2 in range(1, n + 1):
            if i1 * i2 >= n:
                break
            else:
                r += 1
    print(r)


if __name__ == "__main__":
    main()

-from math import ceil -from numba import njit - -    @njit -    def s(n): -        res = 0 -        for i1 in range(1, n + 1): -            for i2 in range(1, n + 1): -                if i1 * i2 >= n: -                    break -                else: -                    res += 1 -        return res - -    r = s(n) +    r = 0 +    for i1 in range(1, n + 1): +        for i2 in range(1, n + 1): +            if i1 * i2 >= n: +                break +            else: +                r += 1