#define LED 2
#define LED2 4
void setup() {
  // put your setup code here, to run once:
  pinMode(LED,OUTPUT);
  pinMode(LED2, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(LED, HIGH);
  digitalWrite(LED2, LOW);
  delay(500);
  digitalWrite(LED,LOW);
  digitalWrite(LED2,HIGH);
   delay(500);
}