def main():

    n = int(input())

    table = [i for i in range(n+1)]

    import math

    def sieve(n):
        ass = []
        is_prime = [True]*(n+1)
        is_prime[0] = False
        is_prime[1] = False

        for i in range(2, int(math.sqrt(n))+1):
            if not is_prime[i]:
                continue
            for j in range(i*2, n+1, i):
                is_prime[j] = False
        for i in range(n+1):
            if is_prime[i]:
                ass.append(i)
        return(ass)

    S = sieve(7500)

    for p in S:
        t = p**2
        for i in range(2, 34):
            if i%2 == 1:
                continue
            j = pow(p, i)
            if j > n:
                break
            k = j
            while k <= n:
                table[k] //= t
                k += j
    #print(table)
    ans = 0
    for a in range(1, n+1):
        ans += math.floor(math.sqrt(n/table[a]))
    print(ans)
    
if __name__ == '__main__':
    main()