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.Globalization;
using System.IO;
using System.Linq;
using System.Text;

namespace AtCoder
{
    internal class Program
    {
        static int ReadInt() { return int.Parse(Console.ReadLine()); }
        static long ReadLong() { return long.Parse(Console.ReadLine()); }
        static int[] ReadInts() { return Console.ReadLine().Split().Select(int.Parse).ToArray(); }
        static long[] ReadLongs() { return Console.ReadLine().Split().Select(long.Parse).ToArray(); }
        static string[] ReadStrings() { return Console.ReadLine().Split(); }

        static void Main(string[] args)
        {
            var n = ReadLong();
            Solve(n);
        }


        internal static void Solve(long n)
        {
            var ans = n.ToString().Length;
            var root = Math.Sqrt(n);
            for (var i = 2; i <= root; ++i)
            {
                if (n % i == 0)
                {
                    var div = (n / i).ToString().Length;
                    if (div < ans)
                    {
                        ans = div;
                    }
                }
            }

            Console.WriteLine(ans);
        }
    }
}