String msg1 = "Please what LED do you wanna turn on(red,blue,green)";
int pin9 = 9;
int pin10 = 10;
int pin11 = 11;
String myLed ;
String msg2 = "Your ";
String msg3 =" LED is turned on";

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(pin9, OUTPUT);
pinMode(pin10, OUTPUT);
pinMode(pin11, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
Serial.println(msg1);
while(Serial.available() == 0){

}
myLed = Serial.readString();
myLed.trim();
Serial.print(msg2);
Serial.print(myLed);
Serial.println(msg3);


if (myLed =="red" || myLed =="Red" ){
  digitalWrite(pin9, HIGH);
  digitalWrite(pin10, LOW);
  digitalWrite(pin11, LOW);
}
if (myLed == "blue" || myLed =="Blue"){
  digitalWrite(pin10, HIGH);
  digitalWrite(pin9, LOW);
  digitalWrite(pin11, LOW);
}
if (myLed == "green" || myLed =="Green"){
  digitalWrite(pin11, HIGH);
  digitalWrite(pin10, LOW);
  digitalWrite(pin9, LOW);
}

}