Competitions

# Math functions

# Guess

Write a program that guesses the number. It is known that it is positive integer and does not exceed some predetermined number **n**.

The guesser is allowed to ask only questions of the form

**? A**

meaning the question "The guessed number is greater than **A**?". To this question, you can get only one of two answers: "**Yes**" or "**No**". The number of asked questions should be minimum for any number not exceeding **n**.

#### Input

One positive integer **n** (**1** ≤ **n** ≤ **2** ·`10`

).^{9}

#### Output

Print the minimum possible number of questions for any number not exceeding **n**.

Input example #1

15

Output example #1

4