import java.util.Scanner;

class Binary2Decimal

{

public static int bin2Dec(String binaryString) throws NumberFormatException

{

int decimal = 0;

int strLength=binaryString.length();

for (int i = 0; i < strLength; i++)

{

if (binaryString.charAt(i) < '0' || binaryString.charAt(i) > '1')

{

throw new NumberFormatException("Not a binary number...");

}

decimal += (binaryString.charAt(i)-'0') * Math.pow(2, strLength-1-i);

}

return decimal;

}

public static void main(String[] args)

{

Scanner input = new Scanner(System.in);

System.out.print("Enter Binary Value : ");

String str = input.nextLine();

try

{

System.out.println("Value = " + bin2Dec(str));

}

catch(NumberFormatException e)

{

System.out.println(e);

}

}

}