int led1 = D3;
int led2 = D2;

void setup() {
    
    pinMode(led1,OUTPUT);
    pinMode(led2,OUTPUT);
}

void loop() {
    
    for (int i = 0; i<5; i++){
        digitalWrite(led1, HIGH);
        digitalWrite(led2, LOW);
        delay(1500);
        digitalWrite(led1, LOW);
        digitalWrite(led2, HIGH);
        delay(1000);
        }
    delay(3000);
}