Scanner s = new Scanner(System.in);
        double amount;
        String from, to;

        double usdToBgn = 1.72;
        double eurtobgn = 1.9558;
        System.out.print("Amount: ");
        amount = s.nextDouble();
        System.out.print("From: ");
        from = s.next();
        System.out.print("To: ");
        to = s.next();

        double result;
        if (from.equals(to)) {
            result = amount;
        } else if (from.equals("USD") && to.equals("BGN")) {
            result = amount * usdToBgn;
        } else if (from.equals("USD") && to.equals("EUR")) {
            result = amount * usdToBgn / eurtobgn;
        } else if (from.equals("BGN") && to.equals("USD")) {
            result = amount / usdToBgn;
        } else if (from.equals("BGN") && to.equals("EUR")) {
            result = amount / eurtobgn;
        } else if (from.equals("EUR") && to.equals("BGN")) {
            result = amount * eurtobgn;
        } else if (from.equals("EUR") && to.equals("USD")) {
            result = amount * eurtobgn / usdToBgn;

        } else {
            System.out.println("Unknown conversion");
            return;
        }
        System.out.printf("Result: %.4f\n", result);
    }