Blue Bridge Cup JavaB group - and especially the number of

[Problems] Description
digital Xiaoming 2,0,1,9 digit contain a very interest (not including the leading 0), 1 to
40, comprising such numbers 1,2,9,10 and 40 to 32, 39 a total of 28, and they are 574.
Will the 1 to n, all such numbers and how much?
[Input format
input line contains two integers n.
[] Output format
output line, comprising an integer, and represents a number satisfying the condition.
[Sample input]
40
[output] Sample
574

[Evaluation Example] Size and conventions used
for evaluation by 20% in Example, 1 ≤ n ≤ 10.
For evaluation by 50% in Example, 1 ≤ n ≤ 100.
For evaluation by 80% in Example, 1 ≤ n ≤ 1000.
For the evaluation all use cases, 1 ≤ n ≤ 10000.

As this problem can take to 10,000 N, the type used in large numbers, to prevent overflow.

import java.math.BigInteger;
import java.util.Scanner;

public  class Main
{
    
    public static boolean fun(int num)
    {
        S String = String.valueOf (NUM); // converts int String 
        char [] = s.toCharArray Art (); // convert the string into an array 
        for ( int I = 0; I <s.length ( ); I ++ )
        {
            if(art[i]=='2' || art[i]=='0'|| art[i]=='1'||art[i]=='9')
            {
                return true;
            }
        }
        return false;
    }

    public static void main(String[] args)
    {
        // TODO Auto-generated method stub
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        
        BigInteger sum = new BigInteger("0");
        for(int i=1;i<=a;i++)
        {
            IF (Fun (I)) // determines whether there 2,0,1,0 
            {
                NUM String = String.valueOf (i); // i is translated into strings 
                a BigInteger One = new new a BigInteger (NUM); // the number of classes into large numbers 
                SUM = sum.add (One); // to satisfy the condition accumulating the number of
                 // System.out.println (SUM);
                
            }
        }
        
        System.out.print(sum);

    }

}