int a=7;
int b=6;
int c=5;
void setup() {
  pinMode(a, OUTPUT);
  pinMode(b,OUTPUT);
  pinMode(c,OUTPUT);
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(a, HIGH);
delay(1000);
digitalWrite(a,LOW);
delay(1000);
digitalWrite(b ,HIGH);
delay(1000);
digitalWrite(b,LOW);
delay(1000);
digitalWrite(c, HIGH);
delay(1000);
digitalWrite(c,LOW);
delay(1000);
}