int switchState = 0;  //variable declaration 

void setup() {
  // put your setup code here, to run once:
  pinMode(2, INPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  switchState = digitalRead(2);

  //if(switchState == LOW)  // the switch is not pressed
  if(switchState == 0)
  {
    digitalWrite(3, HIGH);  // green LED
    digitalWrite(4, LOW); // red LED
    digitalWrite(5, LOW); // red LED
  }
  else  // the switch is pressed
  {
    digitalWrite(3, LOW);
    digitalWrite(4, HIGH);
    digitalWrite(5, LOW);

    delay(250);
    digitalWrite(4, LOW);
    digitalWrite(5, HIGH);
    delay(250);
  }
}