int led1=7;
int led2=6;
int led3=5;
void setup() {
  // put your setup code here, to run once:
  pinMode(7, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(5, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(led1,HIGH);
digitalWrite(led2,LOW);
digitalWrite(led3,LOW);
delay(1000);
digitalWrite(led1,LOW);
digitalWrite(led2,HIGH);
digitalWrite(led3,LOW);
delay(1000);
digitalWrite(led1,LOW);
digitalWrite(led2,LOW);
digitalWrite(led3,HIGH);
delay(1000);
}