int red=8;
int green=5;
void setup() {
  // put your setup code here, to run once:
pinMode(red, OUTPUT);
pinMode(green, OUTPUT);
}
void loop() {

  // put your main code here, to run repeatedly;
digitalWrite(red, HIGH);
digitalWrite(green,LOW);
delay(1000);
digitalWrite(green,HIGH);
digitalWrite(red,LOW);
delay(1000);
}