There are few errors in syntax.  I'm new to java and I can't recognize
why do such errors appear.  Please help. Thank you so much!

<code>
import java.lang.*;
import java.io.*;

class BinaryDecoder{
    public static void main(String args[]) throws IOException{
        InputStreamReader stdin = new InputStreamReader(System.in);
        BufferedReader console = new BufferedReader(stdin);
        System.out.print("Enter a number in binary: ");
        String input = console.readLine();

        //Decimal value of input
        System.out.println("Decimal: " + toDecimal(input));

        //Converts to Octal
        System.out.print("Octal: ");
        for(int counter=input.length()-1; counter>=0; counter-=3){
            //groups the binary digits to 3
            String group=input.substring(counter,counter-2);
            //converts the grouped digit to binary
            System.out.print(toDecimal(group));
        }

        //Converts to Decimal
        public int toDecimal(String s){
            int sum=0;
            for(int counter=s.length()-1; counter>=0; counter--){
                if(s.charAt(counter)=='1'){
                    int exp=s.length()-1-counter;
                    sum+=Math.pow(2,exp);
                }
            }
            return sum;
        }
    }
}

</code>