void setup() {
  // put your setup code here, to run once:
pinMode(5, OUTPUT); //b
pinMode(3, OUTPUT); //c
pinMode(9, OUTPUT); //d
pinMode(2,INPUT_PULLUP);//a
}

void loop() {
  // put your main code here, to run repeatedly:
if (digitalRead(2)==LOW) {
  digitalWrite(5, HIGH);
  digitalWrite(3, LOW);
  digitalWrite(9, LOW);
  delay(3000);
  digitalWrite(5, LOW);
  digitalWrite(3, HIGH);
  digitalWrite(9, LOW);
  delay(3000);
  digitalWrite(5, LOW);
  digitalWrite(3, LOW);
  digitalWrite(9, HIGH);
  delay(3000);
}
else {
  digitalWrite(5, HIGH);
  digitalWrite(3, LOW);
  digitalWrite(9, LOW);
  delay(3000);
  digitalWrite(5, LOW);
  digitalWrite(3, HIGH);
  digitalWrite(9, LOW);
  delay(3000);
  digitalWrite(5, LOW);
  digitalWrite(3, LOW);
  digitalWrite(9, HIGH);
  delay(3000);
}
}