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: Runtime Error)

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

fn main(){
  let (n, k) : (u64, u64) = {
    let mut buf = String::new();
    io::stdin().read_to_string(&mut buf);
    let mut nr = buf.split_whitespace();
    
    ( nr.next().unwrap().parse().unwrap(),
      nr.next().unwrap().parse().unwrap())
  };
  let i_ = (0 .. n).find(|i| n < k.pow(*i as u32)).unwrap();
  println!("{}", i_)
}