UVA - 11296 - Counting Solutions to an Integral Equation (Java Solution)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class Main {

    public static void main(String[] args) throws IOException{
       
        InputStreamReader isr=new InputStreamReader(System.in);
        BufferedReader br=new BufferedReader(isr);
        StringBuffer sb = new StringBuffer("");
        String m="";
       
        while((m=br.readLine())!=null){
            int n=Integer.parseInt(m);
            BigInteger bg=BigInteger.valueOf(n);
            BigInteger result=(bg.divide(BigInteger.valueOf(2))).add(BigInteger.valueOf(2));
            result=result.multiply(result.subtract(BigInteger.ONE)).divide(BigInteger.valueOf(2));
            sb.append(result).append("\n");
        }
        System.out.print(sb);
    }

}