Factorial(BigInteger).java

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'extraLongFactorials' function below.
     *
     * The function accepts INTEGER n as parameter.
     */

    public static void extraLongFactorials(int n) 
    {
        // Write your code here
        BigInteger f = new BigInteger("1");  //initializing the class..
        int i;
        //starting from 2 as 1 is already been taken..
        for(i=2;i<=n;i++)
        {
            f = f.multiply(BigInteger.valueOf(i)); //multiplying the number..
        }
        System.out.println(f);
    }
}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

        int n = Integer.parseInt(bufferedReader.readLine().trim());

        Result.extraLongFactorials(n);

        bufferedReader.close();
    }
}