Installments

class Main {
    public static void main(String[] args) {
	    String principalAmount = "434,62";
		Long principalAmount100 = Long.valueOf(principalAmount.replace(",", ""));
		Long numberOfInstallments = 3L;
		Long installment100 = principalAmount100 / numberOfInstallments;
		String firstInstallment = installment100.toString();
		
		System.out.println("principalAmount=" + principalAmount);
		System.out.println("numberOfInstallments=" + numberOfInstallments);
		System.out.println("firstInstallment=" + format(firstInstallment));
        
        Long lastInstallment = principalAmount100 - 2 * installment100;

		System.out.println("lastInstallment=" + format(lastInstallment.toString()));

    }
    private static String format(String number100) {
        int idx = number100.length()-2;
        return number100.substring(0,idx)+","+number100.substring(idx);
    }
}