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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>

#define vint vector<int>
#define vstr vector<string>
#define vll vector<long long>
#define ll long long
#define pf printf
#define sf scanf
#define sfd(n) scanf("%d", &n)
#define sflf(n) scanf("%lf", &n)
#define sfll(n) scanf("%lld", &n)
#define pfd(n) printf("%d", n)
#define pflf(n) printf("%lf", n)
#define pfll(n) printf("%lld", n)
#define pft	printf("\t")
#define pfn printf("\n")
#define pfk printf(" ")
#define PI 3.1415926
#define MAX 200020
#define M 1e18
#define F -1e6
#define E 1e6

using namespace std;

int main() {
 	int n, k;
	cin >> n >> k;
	int cnt = 0;
	while( n ) {
		n /= k;
		cnt++;
	}
	pfd(cnt);
	
	return 0;
}