String colo ;
void setup() {
  pinMode(2, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(6, OUTPUT);
  Serial.begin(9600);
  // put your setup code here, to run once:

}

void loop() {



 Serial.println(" hello ");
 Serial.print( "by ");
  colo = Serial.readString();
  Serial.println(colo);

  if (colo == "b\n"){
    digitalWrite(2, HIGH);
    digitalWrite(4, LOW);
    digitalWrite(6, LOW);
   
  }
    if (colo == "r\n"){
    digitalWrite(2, LOW);
    digitalWrite(4, HIGH);
    digitalWrite(6, LOW);
  }

    if (colo == "y\n"){
    digitalWrite(2, LOW);
    digitalWrite(4, LOW);
    digitalWrite(6, HIGH);
  }
  // put your main code here, to run repeatedly:

}