Doubling to Reach a Limit

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Start with x=1; each operation doubles x. Given positive N, find the smallest number of operations needed until x >= N. If N=1, the answer is zero.

Input

One positive integer N.

Output

Print the minimum number of doublings.

Subtasks

• Subtask 1 (20%): 1 <= N <= 4.
• Subtask 2 (30%): 1 <= N <= 1000.
• Subtask 3 (50%): 1 <= N <= 1000000000.

Examples

Example 1

Input

17

Output

5

Explanation

The sequence is 1,2,4,8,16,32; the fifth operation first reaches 17.

Example 2

Input

1

Output

0

Explanation

The initial value already meets the target.