int RED =13;
int GREEN =12;
char str;

void setup() {
  pinMode(GREEN,OUTPUT);
  pinMode(RED,OUTPUT);
  Serial.begin(9600);
  Serial.print("Start");

}

void loop() {
  str = Serial.read();
   if(str=='A'){
    digitalWrite(RED,HIGH);
    Serial.println("LED RED ON");
   
   }else if(str =='B'){
    digitalWrite(GREEN,HIGH);
    Serial.println("LED GREEN ON");
   
   }else if(str =='X'){
    digitalWrite(RED,LOW);
    Serial.println("LED RED OFF");
    
   }else if(str =='Y'){
    digitalWrite(GREEN,LOW);
    Serial.println("LED GREEN OFF");
   }
}



//digitalWrite(RED,HIGH);
//delay(1000);
//digitalWrite(RED,LOW);
//delay(1000);
//digitalWrite(GREEN,HIGH);
//delay(1000);
//digitalWrite(GREEN,LOW);
//delay(1000);