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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef int64_t i6;

#define rep(i, n) for (ll i = 0; i < n; ++i)
#define Sort(x) sort(x.begin(), x.end())
#define Sort_rev(x) sort(x.begin(), x.end(), greater<int>())
#define ALL(v) (v).begin(), (v).end()

// π M_PI
// deg = rad*180/M_PI

int main() {
    ll n, k;
    cin >> n >> k;
    ll ans = 0;
    while ( n > pow(k, ans) ) {
        // cout << ans << " " << pow(k, ans) << endl;
        ans++;
    }
    cout << ans << endl;
    return 0;
}