Using One Analog Pin to Read 4 Buttons - Arduino

The idea is to read the resistanse differense between them using resistors.
The buttons are connected in such way that each button add the resistors of the buttons before him to a serial out put.

I used 4 220ohm resistors and 4 buttons.

int sensorPin = A0;    
int sensorValue = 0;  

void setup() {
  pinMode (sensorPin, INPUT_PULLUP);
  Serial.begin (9600);
}

void loop() {
  sensorValue = analogRead(sensorPin);    
  sensorValue =  (map (sensorValue, 18,44, 1, 5));
  if (sensorValue < 5 ) Serial.println (sensorValue); 
}