H. How Ali Sees Black
time limit per test
1 second
memory limit per test
1024 megabytes
input
standard input
output
standard output

$$$Ali$$$ wanted to make a very hard problem, so he thought really hard and after a week of continuous work, he came up with this problem:

You have a set $$$M$$$ containing all numbers from $$$1$$$ to $$$n$$$. In one operation, you can choose an integer $$$x$$$ and subtract it from all numbers that are greater than or equal to it. If a number becomes zero, you remove it from the set. What is the minimum number of operations required to make the set empty?

Input

The only line of input contains one integer $$$n$$$ $$$(1 \le n \le 100)$$$ ,as described in the problem.

Output

Print one integer, the minimum number of operations required to make the set empty.

Examples
Input
1
Output
1
Input
2
Output
2
Input
47
Output
6
Note

In the first example, the set is $$$\{1\}$$$ so we choose $$$x=1$$$, and after this operation, the set will be empty.

In the second example, the set is: $$$\{1,2\}$$$, we can choose $$$x=2$$$ so the set will become: $$$\{1\}$$$ ,and after that we choose $$$x=1$$$.