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 pi 3.1415926535897932384626
using namespace std;
      
struct P{
  int x,y;
  bool operator < (const P &a )const{
    //if(y!=a.y)
    return y>a.y;
  };
};

int a,b,c,d,i,k,n,m,e,dx[10]={1,0,-1,0,1,1,-1,-1},dy[10]={0,1,0,-1,1,-1,1,-1};
int o[1];
int l[1];
int j[1];

long long x,y,z,mod=1000000007;
string r;
//char r[111];

P u[1];
queue<int> q;

stack<int> s;
map<int,int> p;
vector<int> v;

bool as(P a,P b)
{
  if(a.x==b.x)
  return a.y<b.y;
  return a.x<b.x;
}

int f(int n,int m)
{
  if(n<m) return 1;
  return f(n/m,m)+1;
}

int main()
{
  scanf("%d %d",&a,&b);
  printf("%d",f(a,b));
}