Problem:
Score : 300 points

Problem Statement

You are given an integer N.

For two positive integers A and B, we will define F(A,B) as the larger of the following: the number of digits in the decimal notation of A, and the number of digits in the decimal notation of B.

For example, F(3,11) = 2 since 3 has one digit and 11 has two digits.

Find the minimum value of F(A,B) as (A,B) ranges over all pairs of positive integers such that N = A \times B.

Constraints

1 \leq N \leq 10^{10}

N is an integer.

Input

The input is given from Standard Input in the following format:

N

Output

Print the minimum value of F(A,B) as (A,B) ranges over all pairs of positive integers such that N = A \times B.

Sample Input 1

10000

Sample Output 1

3

F(A,B) has a minimum value of 3 at (A,B)=(100,100).

Sample Input 2

1000003

Sample Output 2

7

There are two pairs (A,B) that satisfy the condition: (1,1000003) and (1000003,1). For these pairs, F(1,1000003)=F(1000003,1)=7.

Sample Input 3

9876543210

Sample Output 3

6

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static System.Console;
namespace AtCoder.ABC057
{
    class DigitsInMultiplication
    {
        static long MaxDivisorUnderSQRT(long n)
        {
            for (long i = (long) Math.Sqrt(n); 0 < i; --i)
            {
                if (n % i == 0) return i;
            }
            return 1;
        }
        static int CalDigit(long n)
        {
            if (n == 0) return 0;
            else return 1 + CalDigit(n / 10);
        }
        public static void Main()
        {
            var n = long.Parse(ReadLine().Trim());
            WriteLine(CalDigit(n / MaxDivisorUnderSQRT(n)));
        }
    }
}