Problem:
 Score : 300 points    Problem Statement Given is a positive integer N .
How many tuples (A,B,C) of positive integers satisfy A \times B + C = N ?      Constraints  2 \leq N \leq 10^6  All values in input are integers.         Input Input is given from Standard Input in the following format:  N       Output Print the answer.        Sample Input 1 3      Sample Output 1 3  There are 3 tuples of integers that satisfy A \times B + C = 3 : (A, B, C) = (1, 1, 2), (1, 2, 1), (2, 1, 1) .       Sample Input 2 100      Sample Output 2 473       Sample Input 3 1000000      Sample Output 3 13969985

Solution (Python):
def main(sample_file = ''):

    """ convenient functions
    
    
    
    
    
    """

    """convenient decorator
    
    
        
        
        
        
        
        
        
        
        
        
    """
    
    
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product, combinations_with_replacement 
    
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  
        b, e = 2, 0  
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):   
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict 
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest 
    from copy import deepcopy, copy 
    import operator
    from operator import itemgetter 
    
    
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd
    def gcd(a,b):
        
        
        if a<b:
            a, b = b, a
        while a%b !=0 :
            a, b = b, a%b
        return b

    
    
    
    
    
    

    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)

    
    def sieve_of_eratosthenes(end, typecode="L"):
        
        

        
        import array
        import textwrap
        assert end > 1
        
        
        
        is_prime = array.array("B", (True for i in range(end)))
        
        is_prime[0] = False
        is_prime[1] = False
        
        primes = array.array(typecode)
        
        for i in range(2, end):
            if is_prime[i]:
                primes.append(i)
                for j in range(2 * i, end, i):
                    is_prime[j] = False  
        return primes

    class PrimeFactorization:
        '''初期化にO(NloglogN)/ 因数分解クエリをO(log(k))/ 素数判定クエリをO(1)
        >>> pf = PrimeFactorization(100)
        >>> pf.query(100)
        ((2, 2), (5, 2))
        
        '''
        
        
        
        
        
        
        
        def __init__(self, Num=10**6):
            from collections import defaultdict
            from math import floor
            self.Num = Num
            self.D = [-1] * (Num+1)
            for i in range(2, Num+1):
                if self.D[i] != -1:
                    continue
                self.D[i] = i
                for j in range(1, floor(Num/i)+1):
                    if self.D[j*i] != -1:
                        continue
                    else:
                        self.D[j*i] = i
        
        def query(self, k):
            ans = defaultdict(int)
            tmp = k
            while self.D[tmp] != -1:
                div = self.D[tmp]
                ans[div] += 1
                tmp = tmp//div
            return tuple(ans.items())
        
        def is_prime(self, k):
            return k == self.D[k]

    
    
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    AtoZ = list('abcdefghijklmnopqrsruvwxyz') 
    modpow = lambda a, n, p = MOD: pow(a, n, p) 
    def modinv(a, p = MOD):
        
        
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        
        
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something like:
        >>      pass
        >>  else:
        >>      do something like:
        >>      L[find_root(a)] = L[find_root(a)] + L[find_root(b)]
        >>      L[find_root(b)] = L[find_root(a)]
        >>      
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    
    
    
    class SegTree:
        """
        ref: https://qiita.com/takayg1/items/c811bd07c21923d7ec69
        init(init_val, ide_ele): 配列init_valで初期化 O(N)
        update(k, x): k番目の値をxに更新 O(logN)
        query(l, r): 区間[l, r)をsegfuncしたものを返す O(logN)
        """
        def __init__(self, init_val, segfunc, ide_ele):
            """
            init_val: 配列の初期値
            segfunc: 区間にしたい操作
            ide_ele: 単位元
            n: 要素数
            num: n以上の最小の2のべき乗
            tree: セグメント木(1-index)
            """
            n = len(init_val)
            self.segfunc = segfunc
            self.ide_ele = ide_ele
            self.num = 1 << (n - 1).bit_length()
            self.tree = [ide_ele] * 2 * self.num
            
            for i in range(n):
                self.tree[self.num + i] = init_val[i]
            
            for i in range(self.num - 1, 0, -1):
                self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

        def update(self, k, x):
            """
            k番目の値をxに更新
            k: index(0-index)
            x: update value
            """
            k += self.num
            self.tree[k] = x
            while k > 1:
                self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
                k >>= 1

        def query(self, l, r):
            """
            [l, r)のsegfuncしたものを得る
            l: index(0-index)
            r: index(0-index)
            """
            res = self.ide_ele
            l += self.num
            r += self.num
            while l < r:
                if l & 1:
                    res = self.segfunc(res, self.tree[l])
                    l += 1
                if r & 1:
                    res = self.segfunc(res, self.tree[r - 1])
                l >>= 1
                r >>= 1
            return res

    
    
    
    
    
    
    
    

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    
    def warshall_floyd(number_vertex, XYD, shift_one_for_vertex=False):
        
        
        
        
        
        d = [[float("inf")]*number_vertex for i in range(number_vertex)]
        for x, y, dist in XYD:
            if shift_one_for_vertex:
                x = x - 1
                y = y - 1
            d[x][y] = dist
            d[y][x] = dist
        for i in range(number_vertex):
            d[i][i] = 0 
        for k in range(number_vertex):
            for i in range(number_vertex):
                for j in range(number_vertex):
                    d[i][j] = min(d[i][j],d[i][k] + d[k][j])
        return d


    """ initialize variables and set inputs
    
        
        
            
            
    
        
        
        
        
        
        
        
    
        
        
        
        
    
        
        
    """

    
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    r_float = lambda: float(r())
    R = lambda: list(map(int, r().split()))
    R_str = lambda: r().split()
    R_map = lambda: map(int, r().split())
    R_float = lambda: list(map(float, r().split()))
    R_tuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    
    
    
    
    
    
    
    """

    
    if sample_file:
        sys.stdin = open(sample_file)
        
    
    
    

    N = r_int()
    ans = 0
    for i in range(1, N):
        ans += (N-1)//i
    print(ans)
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    


    
    
    

    """memo: how to use defaultdict of list
    
    Dic = defaultdict(list)
    
    Dic[x].append(y)
    
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    
    >>> a = 5
    >>> bin_str_a = format(a, '
    >>> print(bin_str_a)
    0b0101 
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Solution (Python):
def main():
    N = int(input())

    ans = 0
    for A in range(1, N):
        ans += (N-1) // A
    
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())

ans = sum((n-1)//i for i in range(1,n))
print(ans)

Solution (Python):
MAX = 1000001; 
  


factor = [0]*(MAX + 1); 
  



def generatePrimeFactors(): 
    factor[1] = 1; 
  
    
    
    for i in range(2,MAX): 
        factor[i] = i; 
  
    
    
    for i in range(4,MAX,2): 
        factor[i] = 2; 
  
    
    
    
    
    
    i = 3; 
    while(i * i < MAX): 
        
        
        if (factor[i] == i): 
            
            
            j = i * i; 
            while(j < MAX):  
                
                
                
                if (factor[j] == j): 
                    factor[j] = i; 
                j += i; 
        i+=1; 
  


def calc(n): 
    if (n == 1): 
        return 1; 
    ans = 1; 
  
    
    
    
    dup = factor[n]; 
  
    
    
    
    c = 1; 
  
    
    
    
    j = int(n / factor[n]); 
  
    
    
    while (j > 1): 
        
        
        
        
        if (factor[j] == dup): 
            c += 1; 
  
        
        
        
        
        
        
        else: 
            dup = factor[j]; 
            ans = ans * (c + 1); 
            c = 1; 
  
        
        
        j = int(j / factor[j]); 
  
    
    
    ans = ans * (c + 1); 
  
    return ans;
generatePrimeFactors()
n=input()
c=0
for i in range(1,n):
    c+=calc(n-i)
print c

Solution (Python):
N = int(input())

ans = 0
for A in range(1, N):
  ans += (N-1)//A
print(ans)

Solution (Python):


N = int(input())

print(sum([(N - 1) // i for i in range(1, N)]))

Solution (Python):
n=int(input())
prod=n-1
ans=0
for i in range(1,n):
    fi=i
    cnt2=prod//fi
    ans+=cnt2
print(ans)

Solution (Python):
n = int(input())
ans = 0
for i in range(1,n):
    ans += (n-1)//i
print(ans)

Solution (Python):
N=int(input())
ans=0
for i in range(1,N):
    if N%i==0:
        ans+=(N-1)//i
    else:
        ans+=N//i
print(ans)

Solution (Python):
N = int(input())


print(sum([(N-1)//i for i in range(1,N)]))

Solution (Python):
n=int(input())

s=0
for a in range(1,n+1):
    s+=(n-1)//a

print(s)

Solution (Python):
n=int(input())
s=0
for i in range(n):
    j=i+1
    a=n//j
    c=n%j
    if c==0:
        s+=a-1
    else:
        s+=a
print(s)

Solution (Python):
import sys
input=sys.stdin.readline

n=int(input())

ans=0
for a in range(1,10**6+1):
    for b in range(1,10**6//a+1):
        if a*b<n:
            ans+=1

print(ans)

Solution (Python):
N = int(input())
ans = 0
for i in range(1, N):
  for j in range(1, N):
    if(N - i * j > 0):
      ans += 1
    else:
      break
print(ans)

Solution (Python):
N=int(input())

ans=0
for i in range(1,N):
  for j in range(1,N):
    if i*j<N:
      ans+=1
    else:
      break
print(ans)

Solution (Python):
N = int(input())

ans = 0
for a in range(1, N):
    ans += N//a
    if N%a == 0:
        ans -= 1
print(ans)

Solution (Python):
n = int(input())

ans = 0

for i in range(1,n):
  x = (n-1) // i
  ans += x
  
print(ans)

Solution (Python):
N = int(input())
ans = 0

for i in range(1, N):
    A = i
    B_no_kazu = (N - 1) // i

    ans += B_no_kazu
print(ans)

Solution (Python):



n = int(input())

ret = 0
for i in range(1, n):
    ret+=(n-1)//i
print(ret)

Solution (Python):








def solve(N):
    ans = 0
    for a in range(1, N):
        b = N // a
        if N % a == 0: b -= 1
        ans += b
    print(ans)


if __name__ == '__main__':
    
    N = int(input())
    
    
    
    
    solve(N)

Solution (Python):
import sys



def input():
    return sys.stdin.readline().strip()


def input_int():
    return int(input())


def input_int_list():
    return [int(i) for i in input().split()]


def main():
    n = input_int()
    ans = 0
    for i in range(1, n):
        ans += (n - 1) // i
    print(ans)

    return


if __name__ == "__main__":
    main()

Solution (Python):
n = int(input())
ans = 0
for i in range(1,n):
    ans += ((n-1)//i)
print(ans)

Solution (Python):
N = int(input())

lst = [1]*N
lst[0] = 0

for i in range(2,N):
  j = 1
  while i*j < N:
    lst[i*j] += 1
    j += 1
    
print(sum(lst))

Solution (Python):
n=int(input())
ans=0
for a in range(1,n):
    ans+=n//a
    if n%a==0:
        ans-=1
print(ans)

Solution (Python):
n = int(input())
ans = 0
for i in range(1,n):
    ans += (n-1)//i
    
    
print(ans)

Solution (Python):
n=int(input())
ans=0
for i in range(1,n):
    ans+=(n-1)//i
print(ans)

Solution (Python):

import sys, re
from collections import deque, defaultdict, Counter, OrderedDict
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from heapq import heappush, heappop, heapify, nlargest, nsmallest
def STR(): return list(input())
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def list2d(a, b, c): return [[c] * b for i in range(a)]
def sortListWithIndex(listOfTuples, idx):   return (sorted(listOfTuples, key=lambda x: x[idx]))
def sortDictWithVal(passedDic):
    temp = sorted(passedDic.items(), key=lambda kv: (kv[1], kv[0]))
    toret = {}
    for tup in temp:
        toret[tup[0]] = tup[1]
    return toret
def sortDictWithKey(passedDic):
    return dict(OrderedDict(sorted(passedDic.items())))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

n = INT()

a = 1
ans = 0
while(n/a>1):
    ans+=ceil(n/a) - 1


    a+=1
print(int(ans))

Solution (Python):
N = int(input())

max_a = int(N ** 0.5)+2
cnt = 0
for a in range(1, max_a):
  for b in range(a, N+1):
    if a*b >= N:
      break
    elif a == b:
      cnt += 1
    else:
      cnt += 2
        

print(cnt)

Solution (Python):
N = int(input())
ans = 0
for i in range(1,N):
    j = 1
    while i*j < N:
        ans += 1
        j += 1
print(ans)

Solution (Python):
n=int(input())

cnt=0
for a in range(1,int(n**0.5)+1):
    for b in range(a,n+1):
        if a*b<n:
            if a==b:
                cnt+=1
            else:
                cnt+=2
        else:
            break

print(cnt)

Solution (Python):
N = int(input())
ans = 0
for n in range(1,N):
    ans += (N-1)//n
print(ans)

Solution (Python):
import math
n=int(input())
ans=0
for i in range(1,n):
    ans+=n//i
    ans-=n//((n*i)//math.gcd(n,i))
print(ans)

Solution (Python):
n=int(input())
ans=0
for i in range(1,n):
    ans+=(n-1)//i
print(ans)

Solution (Python):
n=int(input())
ans=0
for a in range(1,n):
  ans+=(n-1)//a
print(ans)

Solution (Python):
N = int(input())
ans = 0
for i in range(1,N):
    ans += (N-1)//i
print(ans)

Solution (Python):
import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c for j in range(b)] for i in range(a)]
def list3d(a, b, c, d): return [[[d for k in range(c)] for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e for l in range(d)] for k in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10**9)
INF = 10**19
MOD = 10**9 + 7
EPS = 10**-10

N = INT()
ans = 0
for a in range(1, N+1):
    for b in range(1, N+1):
        if a*b >= N:
            break
        ans += 1
print(ans)

Solution (Python):
import sys

readline = sys.stdin.readline
MOD = 10 ** 9 + 7
INF = float('INF')
sys.setrecursionlimit(10 ** 5)


def main():
    N = int(readline())
    ans = 0

    for a in range(1, N):
        for b in range(1, N):
            x = a * b
            if x >= N:
                break
            ans += 1

    print(ans)


if __name__ == '__main__':
    main()

Solution (Python):
N = int(input())

ans = 0
for a in range(1, N + 1):
    if N % a == 0:
        ans += N // a - 1
    else:
        ans += N // a

print(ans)

Solution (Python):
N=int(input())
count=0
for A in range(1,N):
    count+=(N-1)//A
print(count)

Solution (Python):
N = int(input()) - 1
ans = 0
for A in range(1, N+1):
  ans += N // A
print(ans)

Solution (Python):
def main():
    n = int(input())
    dp = [0]*(n+1)
    for i in range(1,n+1):
        j = 1
        while i*j <= n:
            dp[i*j] += 1
            j += 1

    
    pairs = 0
    for c in range(1,n):
        x = n-c
        count = dp[x]
        
        pairs += count

    print(pairs)
    

main()

Solution (Python):
import sys, io, os, re
from bisect import bisect, bisect_left, bisect_right, insort, insort_left, insort_right
from pprint import pprint
from math import sin, cos, pi, radians, sqrt, floor, ceil
from copy import copy, deepcopy
from collections import deque, defaultdict
from fractions import gcd
from functools import reduce
from itertools import groupby, combinations
from heapq import heapify, heappush, heappop



n1 = lambda: int(sys.stdin.readline().strip())
nn = lambda: list(map(int, sys.stdin.readline().strip().split()))
f1 = lambda: float(sys.stdin.readline().strip())
fn = lambda: list(map(float, sys.stdin.readline().strip().split()))
s1 = lambda: sys.stdin.readline().strip()
sn = lambda: list(sys.stdin.readline().strip().split())
nl = lambda n: [n1() for _ in range(n)]
fl = lambda n: [f1() for _ in range(n)]
sl = lambda n: [s1() for _ in range(n)]
nm = lambda n: [nn() for _ in range(n)]
fm = lambda n: [fn() for _ in range(n)]
sm = lambda n: [sn() for _ in range(n)]

def array1(n, d=0): return [d] * n
def array2(n, m, d=0): return [[d] * m for x in range(n)]
def array3(n, m, l, d=0): return [[[d] * l for y in xrange(m)] for x in xrange(n)]
def linc(A, d=1): return list(map(lambda x: x + d, A))
def ldec(A, d=1): return list(map(lambda x: x - d, A))

N = n1()

ans = 0
for i in range(1, N):
    ans += (N-1) // i 

print(ans)

Solution (Python):
from collections import defaultdict
def Sieve_of_Eratosthenes(maxA):
    lst = [-1]*(maxA+1)
    lst[0] = 0
    lst[1] = 1
    for i in range(2, maxA+1):
        if lst[i] == -1:
            for g in range(i, maxA+1, i):
                if lst[g] == -1:
                    lst[g] = i
    return lst

def factorization(n):  
    d = defaultdict(int)
    now = n
    while True:
        if now == lst[now]:
            if now != 1:
                d[now] += 1
            break
        r = lst[now]
        while now % r == 0:
            now //= r
            d[r] += 1
    ans = 1
    for i, m in d.items():
        ans *= (m+1)
    return ans

n = int(input())

ans = 0
lst = Sieve_of_Eratosthenes(n+1)
for c in range(1, n):
    ans += factorization(n-c)

print(ans)

Solution (Python):
import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))  
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))  
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())  
def LS2(): return list(sys.stdin.readline().rstrip())  


N = I()


print(sum((N-1)//i for i in range(1,N)))

Solution (Python):
N = int(input())

def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    
    return divisors

ans = 0
"""
for c in range(1,N):
    ans += len(make_divisors(N-c))
print(ans)
"""

for a in range(1,N):
    ans += (N-1)//a
print(ans)

Solution (Python):
import math
n = int(input())

c = 0
for i in range(1,n):
    if n % i == 0:
        c += ((n / i) -1)
    else:
        c += math.floor(n / i)

print(int(c))

Solution (Python):
n=int(input())
ans=0
for i in range(1,n+1):
  for j in range(1,(n+i-1)//i):
    if i*j<n:ans+=1
print(ans)

Solution (Python):
n=int(input())
cnt=0
for i in range(1,n):
  cnt+=(n-1)//i
print(cnt)

Solution (Python):
def main():
    import sys
    input = sys.stdin.readline
    sys.setrecursionlimit(10**7)
    from collections import Counter, deque
    from collections import defaultdict
    from itertools import combinations, permutations, accumulate, groupby, product
    from bisect import bisect_left,bisect_right
    from heapq import heapify, heappop, heappush
    from math import floor, ceil,pi,factorial
    from operator import itemgetter
    def I(): return int(input())
    def MI(): return map(int, input().split())
    def LI(): return list(map(int, input().split()))
    def LI2(): return [int(input()) for i in range(n)]
    def MXI(): return [[LI()]for i in range(n)]
    def SI(): return input().rstrip()
    def printns(x): print('\n'.join(x))
    def printni(x): print('\n'.join(list(map(str,x))))
    inf = 10**17
    mod = 10**9 + 7

    n=I()
    ans=0
    for i in range(1,n+1):
        for j in range(1,n//i+1):
            if i*j<n:
                ans+=1
                
    print(ans)

        
        
        
        



        
        
        
        
        
    
if __name__=="__main__":
    main()

Solution (Python):
n = int(input())
big = 10**6+1
ans = [0 for _ in range(big)]
for i in range(1,big):
  now = i
  while now < big:
    ans[now] += 1
    now += i

print(sum(ans[:n]))

Solution (Python):
n = int(input())
ans = 0
for a in range(1,n):
    if n % a:
        ans += n // a
    else:
        ans += n // a - 1
print(ans)

Solution (Python):

"""
Created on Sat Sep 19 20:17:59 2020

@author: liang
"""

N = int(input())

ans = 0

for i in range(1,N):
    ans += (N-1)//i
print(ans)

Solution (Python):
a = int(input())
cnt = int(0)
for i in range(1, a):
    cnt += (a-1) // i
print(cnt)