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 rep(i, a, b) for (int i = a; i < (int)(b); ++i)
#define rrep(i, a, b) for (int i = b - 1; i >= (int)(a); --i)

using namespace std;

using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;

// constexpr int M = 32;
// constexpr char CH_INT[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

int main() {
    int n, k;
    cin >> n >> k;

    // char str[M];
    // rep(i, 0, M) { str[i] = '\0'; }

    int length = 0;
    while (true) {
        // str[length++] = CH_INT[n % k];
        ++length;
        n = n / k;
        if (n == 0) { break; }
    }

    // rrep(i, 0, length) {
    //     cout << str[i];
    // }
    // cout << endl;

    cout << length << endl;
    return 0;
}