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>
//#include <ext/pb_ds/tree_policy.hpp>
//#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
//using namespace __gnu_pbds;

#define LL       long long
#define DS       pair<LL, LL>
#define READ(f)  freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)

const int N = 3e5 + 5;
const int MOD = 1e9 + 7;
const double PI = 2 * acos(0.0);
//template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

int main() {
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    LL n, k;
    cin >> n >> k;
    LL ans = log10(n) / log10(k) + 1;
    printf("%lld\n", ans);
    return 0;
}