int a=12;
int b=27;
int c=25;
void setup() {
  Serial.begin(115200);
  pinMode(a,OUTPUT);
  pinMode(b, OUTPUT);
  pinMode(c, OUTPUT);
  }


void loop()
 {
   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);
}