can anyone Modify then Explain the below code?

import java.util.Scanner;

import java.math.$*$;

public class LargeFactorial $\{$

public static void main$($String$[]$ args$)\{$

Scanner input $=$ new Scanner$($System$.$in$)$;

System.out.print$("$Enter an integer: $")$;

int n $=$ input.nextInt$()$;

System.out.println$($n $+"!$ is

$"+$ factorial$($n$))$;

$\}$

public static BigInteger factorial$($long n$)\{$

BigInteger result $=$ BigInteger.ONE; $//$ Assign $1$ to result

for $($int i $=1$; i $<=$ n; i$++)//$ Multiply each i

result $=$ result.multiply$($new BigInteger$($i$+""))$;

return result;

$\}$

$\}$