public static void main(String[] args) {
		// TODO Auto-generated method stub
		String number = "77777777777777777777777777777777777777777777777777777777";
		BigInteger number2 = OtherBaseToDec(number, 10);
		System.out.println(number2);
		
//		BigInteger base16 = new BigInteger("16");
//		System.out.println(base16.pow(16));
		
		
		
		
	}
	
	public static BigInteger OtherBaseToDec(String number, int base) {
        BigInteger result = new BigInteger("0");
        BigInteger baseBigInteger = BigInteger.valueOf(base);
        number = number.toUpperCase();
        
		String HEX = "0123456789ABCDEF";
        for (int i = 0; i < number.length(); i++) {
        	BigInteger hexIndex = new BigInteger(HEX.indexOf(number.charAt(i)) + " ");
			BigInteger value = baseBigInteger.pow(number.length()-i-1 ).multiply(hexIndex) ;
        	result = result.add(value);
		}
        
		return result;
    }
	
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