int RLED = 5;
int BLED = 13;

void setup() {
  // Initalize digital pin RLED (pin 5) as output
pinMode (RLED, OUTPUT);
// Initalize digital pin BLED (pin 13) as output
pinMode (BLED, OUTPUT);
}

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