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;

#define int long long
#define ll long long
#define pb push_back
#define mp make_pair
#define f(i,a,n) for(int i=a ; i<(int)n ; i++)
#define rf(i,n,a) for(int i=n ; i>=a ; i--)
#define F first
#define S second
#define all(c) (c).begin(),(c).end()
#define sz(v) (int)(v).size()
#define fill(a,v) memset(a,v,sizeof(a))
#define d1(a) cout << a << "\n"
#define d2(a,b) cout << a << " " << b << "\n"
#define d3(a,b,c) cout << a << " " << b << " " << c << "\n"
#define d4(a,b,c,d) cout << a << " " << b << " " << c << " " << d << "\n"
#define fast ios:: sync_with_stdio(false),cin.tie(nullptr);

typedef long double ld;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef pair<pii,int> ppi;
typedef vector<pii> vpi;

const int inf = 1e9;
const int inf64 = 1e18;
const int MOD = inf + 7;
int lg(int n , int k)
{
	ld x = log(n);
	ld y = log(k);
	
	x = x/y;
	int ans = x+1;
	return ans;
}
int32_t main(){
	fast;
	int n,r;
	cin >> n >> r;
	cout << lg(n,r);
}