#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define DONT_KNOW "I_dont_know"
#define BASE_POWER 2
#define STARTING_INDEX 2

void printIDontKnow()
{
    printf("%s", DONT_KNOW);
    exit(0);
}

int midterm_quiz_q2(long long n);

//Uncomment the first line in main if you don't know the answer.
//Otherwise, do not change main!!!
int main()
{
    // printIDontKnow();

    long long n;
    if (scanf("%lld", &n) != 1)
    {
        return 1;
    }
    printf("%d", midterm_quiz_q2(n));
    return 0;
}

/*
 * this function gets a number and returns if it has dividers different from 1
 *  and itself.
 * input:
 *  1. int num: the number to be checked.
 * output(bool):
 *  true if the number has dividers.
 */
bool hasDividers(int num)
{
    bool isDividers = false;

    for (int i = 2; i < num; i++)
    {
        double temp = (double)num / i;
        if (((int)temp) == temp)
        {
            isDividers = true;
        }
    }

    return isDividers;
}

long long power(int base, int exponent)
{
    long long result = base;

    for (int i = 1; i < exponent; i++)
    {
        result *= base;
    }

    return result;
}

int midterm_quiz_q2(long long n)
{
    int numberOfNumbers = 0, i = STARTING_INDEX + 1;
    long long current = power(BASE_POWER, STARTING_INDEX) - 1;

    while (current <= n)
    {
        if (!hasDividers(current))
        {
            numberOfNumbers++;
        }

        current = power(BASE_POWER, i) - 1;
        i++;
    }

    return numberOfNumbers;
}