#define LedRed 27
#define LedBlue 26
void setup() {
pinMode(LedRed, OUTPUT);
pinMode(LedBlue, OUTPUT);
}

void loop() {
digitalWrite(LedRed, HIGH);
digitalWrite(LedBlue, LOW);
delay(1000);
digitalWrite(LedRed, LOW);
digitalWrite(LedBlue, HIGH);
delay(1000);
}