int led1=2;
int led2=3;
int led3=4;
int led4=5;

void setup() {
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  Serial.begin(9600);
  // put your setup code here, to run once:

}

void loop() {
  sayi=random(1, 5);
  if(sayi==1) {
  Serial.println("led1 yandı");
  digitalWrite(led1, HIGH);
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);
  delay(1000);
  Serial.println("led 1 söndür")
  delay(500);
  }
  
  // put your main code here, to run repeatedly:

}