Raspberry PI and Arduino Communication [Arduino]

void setup() {
  //Initiating serial communication and flushing serial port, just for good measure
  Serial.begin(9600);
  Serial.flush();
}

byte expected_byte1 = 0x31;
byte expected_byte2 = 0x32;

void loop() {
  // Check if there is something on the serial port
  if (Serial.available()) {
    //read available data, save to recieved_data
    int recieved_data = Serial.read();

    //does the recieved data match our expectations?
    if (recieved_data == expected_byte1) {
      Serial.print("You sent the number 1!");
      delay(50);
    }

    //Other expectation for concept purposes
    if (recieved_data == expected_byte2) {
      Serial.print("You sent the number 2!");
      delay(50);
    }
  }
}