int LED1=1;
int LED2=2;
int LED3=3;
int LED4=4;
int LED5=5;
int LED6=6;

void setup() {
  // put your setup code here, to run once:
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(LED4, OUTPUT);
pinMode(LED5, OUTPUT);
pinMode(LED6, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(LED1, HIGH);
delay(500);
digitalWrite(LED1, LOW);
digitalWrite(LED2, HIGH);
delay(500);
digitalWrite(LED2, LOW);
digitalWrite(LED3, HIGH);
delay(500);
digitalWrite(LED3, LOW);
digitalWrite(LED4, HIGH);
delay(500);
digitalWrite(LED4, LOW);
digitalWrite(LED5, HIGH);
delay(500);
digitalWrite(LED5, LOW);
digitalWrite(LED6, HIGH);
delay(500);
digitalWrite(LED6, LOW);

}