//Header section
int LED1 =6;
int LED2 =7;

void setup() {
  // put your setup code here, to run once:
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(LED1, HIGH);
digitalWrite(LED2, LOW);
delay(1000);//1000 milisec

digitalWrite(LED1, LOW);
digitalWrite(LED2, HIGH);
delay(1000);//1000 milisec
}