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>
using namespace std;

#if DEBUG && !ONLINE_JUDGE
  #include "header.h"
#else
  #define debug(args...)
#endif

typedef vector<int> vi;
typedef pair<int,int> ii;
typedef long long lli;
typedef long double ld;

#define pb push_back
#define all(x) x.begin(),x.end()
#define SZ(x) (int)(x).size()
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define rep(i,a,b) for(auto i=(a);i<b;i++)

#define INF (int)1e9
#define EPS 1e-9
#define MOD 1000000007
void preprocess(void) {
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.precision(20);
  preprocess();
  int n, k; cin>>n>>k;
  int c = 0;
  while(n>0) {
    n/=k;
    c++;
  }
  cout<<c<<endl;
}