byte led1 = 3;
byte led2 = 4;


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


void loop() {
  digitalWrite(led1,HIGH);
  digitalWrite(led2,HIGH);
  delay(1000);
  digitalWrite(led1,LOW);
  digitalWrite(led2,LOW);
  delay(1000);
}