int redPin=11;
int greenPin=12;
int bluePin=13;
String myColour;
String msg="What colour LED? ";
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(redPin, OUTPUT);
pinMode(greenPin,OUTPUT );
pinMode(bluePin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
Serial.println(msg);
while(Serial.available()==0){ 
}
myColour = Serial.readString();
if (myColour == "RED") {
  digitalWrite(redPin, HIGH);
  digitalWrite(greenPin, LOW);
  digitalWrite(bluePin, LOW);
}
if (myColour == "GREEN") {
  digitalWrite(redPin, LOW);
  digitalWrite(greenPin, HIGH);
  digitalWrite(bluePin, LOW);
}
if (myColour == "BLUE") {
  digitalWrite(redPin, LOW);
  digitalWrite(greenPin, LOW);
  digitalWrite(bluePin, HIGH);
}
delay(100);
}