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++ (GCC 9.2.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#include <string>
#include <cstring>
#include <algorithm>
#include <math.h>
#include <map>
#include <bitset>
#include <cmath>
#include <set>

#define INF 1000000000000
#define MOD 1000000007 //10^9+7:合同式の法
#define JUUHATI 1000000000000000000 
#define JUUHATIPLUS 1000000000000000001 

using namespace std;
typedef long long ll;

//マクロ
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define REPD(i,n) for(ll i=n-1;i>=0;i--)
#define FOR(i,a,b) for(ll i=a;i<=(ll)(b);i++)
#define FORD(i,a,b) for(ll i=a;i>=(ll)(b);i--)


int main(){
    long long N,K,rs=0;
    cin >> N >> K;

    while(N > 0){
        N /= K;
        rs++;
    }
    
    cout << rs << endl;
}