Problem:
Score : 200 points

Problem Statement

Given is an integer N. Find the number of digits that N has in base K.

Notes

For information on base-K representation, see Positional notation - Wikipedia.

Constraints

All values in input are integers.

1 \leq N \leq 10^9

2 \leq K \leq 10

Input

Input is given from Standard Input in the following format:

N K

Output

Print the number of digits that N has in base K.

Sample Input 1

11 2

Sample Output 1

4

In binary, 11 is represented as 1011.

Sample Input 2

1010101 10

Sample Output 2

7

Sample Input 3

314159265 3

Sample Output 3

18

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

use std::io;

fn read_line() -> String {
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

fn main() {
    let input = read_line().split_whitespace().map(|x|x.parse::<i64>().unwrap()).collect::<Vec<i64>>();
    let mut N = input[0];
    let K = input[1];

    let mut count:i64 = 0;

    loop {
        if N >= K {
            N = N/K;
            count+=1;
        }else{
            break;
        }
    }

    println!("{}",count+1);
}