   // initialize the digital pin as an output.
   Serial.begin(9600);
   pinMode(ledGreen, OUTPUT);     
-  pinMode(ledYellow, OUTPUT);     
+  pinMode(ledRed, OUTPUT);     
 }
 
 // the loop routine runs over and over again forever:

    //You have to subtract '0' from the read Byte to convert from text to a number.
    byteRead=byteRead-'0';
    
    //0 laptops, show yellow
    if(byteRead==0){
          digitalWrite(ledGreen, LOW); //turn off green
          digitalWrite(ledYellow, HIGH); //turn on yellow
    }
    
    //More than 0 laptops, show green LED
    if(byteRead>0){
          digitalWrite(ledYellow, LOW); //turn off yellow
          digitalWrite(ledGreen, HIGH); //turn on green
      }

}

 
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int ledRed = 13;
int ledGreen = 12;
int val = 0;

