#define LED1 PB4
#define LED2 PB3
#define LED3 PB5

void setup() {
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);

}

void loop() {
  digitalWrite(LED1, HIGH);
  delay(1000);
  digitalWrite(LED1, LOW);
  digitalWrite(LED2, HIGH);
  delay(1000);
  digitalWrite(LED2, LOW);
  digitalWrite(LED3, HIGH);
  delay(1000);
  digitalWrite(LED3, LOW);

}