void setup() {
  // put your setup code here, to run once:
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(A0, OUTPUT);
pinMode(A1, OUTPUT);
pinMode(A2,  OUTPUT);
pinMode(A3, OUTPUT);

}

void loop() {
// put your main code here, to run repeatedly:

//write '4'

digitalWrite(3, HIGH);
digitalWrite(2,HIGH);
digitalWrite(5,HIGH);
digitalWrite(A2, HIGH);
digitalWrite(4, LOW);
digitalWrite(A0, LOW) ;
digitalWrite(A1, LOW) ;
digitalWrite(A3, LOW) ;
delay(500);
}