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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input) {
  var line = input.split(' ');
  var N = Number(line[0]);
  var K = Number(line[1]);
  var log2 = Math.ceil(Math.log2(N));
  // console.log('log2=' + log2);
  var log10 = Math.ceil(Math.log10(N + 1));
  // console.log('log10=' + log10);
  if (K == 2) {
    console.log(log2);
  } else if (K == 10) {
    console.log(log10);
  } else {
    for (var i = log10; i <= log2; i ++) {
      var n = Math.pow(K, i);
      // console.log('n(' + i + ')=' + n);
      if (N <= n) {
        console.log(i);
        break;
      }
    }
  }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));