Problem:
Score : 300 points

Problem Statement

As a token of his gratitude, Takahashi has decided to give his mother an integer sequence.
The sequence A needs to satisfy the conditions below:

A consists of integers between X and Y (inclusive).

For each 1\leq i \leq |A|-1, A_{i+1} is a multiple of A_i and strictly greater than A_i.

Find the maximum possible length of the sequence.

Constraints

1 \leq X \leq Y \leq 10^{18}

All input values are integers.

Input

Input is given from Standard Input in the following format:

X Y

Output

Print the maximum possible length of the sequence.

Sample Input 1

3 20

Sample Output 1

3

The sequence 3,6,18 satisfies the conditions.

Sample Input 2

25 100

Sample Output 2

3

Sample Input 3

314159265 358979323846264338

Sample Output 3

31

Solution in Rust (1.15.1) (judge verdict: Accepted)

extern crate core;

use std::io::{self, Read};

fn main() {
    let mut input = String::new();
    io::stdin().read_to_string(&mut input).unwrap();
    let output = run(input);
    println!("{}", output);
}

fn run(input: String) -> String {
    let list: Vec<i64> = input
        .split_whitespace()
        .map(|x| x.parse::<i64>().unwrap())
        .collect();
    let x = list[0];
    let y = list[1];

    let mut vec: Vec<i64> = Vec::new();
    vec.push(x);
    loop {
        let &last = vec.last().unwrap();
        let last2 = last * 2;
        if last2 <= y {
            vec.push(last2);
        } else {
            break;
        }
    }

    vec.len().to_string()
}