Competitions

# ДОРЕШИВАНИЕ 2014 ACM-ICPC Украина, 2ой Раунд Украина, Сентябрь 13

# Numbairs

Consider the number of the form **a** ^ (**a** ^ (**a** ^ ...) where **a** is a positive integer that can appear in the notation twice or more, **^** is power operation. Let us call such numbers numbairs (which stands for number + stairs). For instance **27** = **3** ^ **3** and **16** = **2** ^ (**2** ^ **2**) are numbairs. Number **1** is numbair too since **1** = **1** ^ **1**. Find out how many numbairs are there between **1** and **n** inclusive.

#### Input

One integer **n** (**1** ≤ **n** ≤ `10`

).^{9}

#### Output

Print the number of numbairs not exceeding **n**.

Input example #1

5

Output example #1

2