RF Shield non-latching

/*The following 4 pin definitions,correspond to 4 buttons on the remote control(The telecontroller is Remote Wireless Keynob 315MHz(SKU:FIT0355))*/
int D1 = 8;    //The digital output pin 1 of decoder chip(SC2272)
int D2 = 9;    //The digital output pin 2 of decoder chip(SC2272)
int D3 = 10;   //The digital output pin 3 of decoder chip(SC2272)
int D4 = 11;   //The digital output pin 4 of decoder chip(SC2272)


void setup()
{
  Serial.begin(9600);
  /*The four pins order below correspond to the 4 buttons on the remote control.*/
  pinMode(D4, INPUT);  //Initialized to input pin, in order to read the level of the output pins from the decoding chip
  pinMode(D2, INPUT);  
  pinMode(D1, INPUT);   
  pinMode(D3, INPUT);  
}

void loop()
{
       Serial.print(digitalRead(D4));  //Read individually output pins of the decoder chip,and put them on the serial monitor 
       Serial.print(digitalRead(D2));
       Serial.print(digitalRead(D1));
       Serial.println(digitalRead(D3));
}