#define LED 13

void setup() {
  // put your setup code here, to run once:
  pinMode(LED , OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(LED, HIGH);
  delay(1000);// wait for 1000 miliseconds
  digitalWrite(LED,LOW);
  delay(1000);// wait for 1000 miliseconds
}