int lightup;
void setup() 
{
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  Serial.begin(9600);
  Serial.print("Which LED will you like to light up?");
  
}

void loop(){
  Serial.flush();
  while(Serial.available()==0){}
  int lightup = Serial.parseInt();
   switch(lightup){
     case 1:
     analogWrite(2,HIGH);
     analogWrite(3,LOW);
     analogWrite(4,LOW);
     analogWrite(5,LOW);
     analogWrite(6,LOW);
     break;
     case 2:
      analogWrite(2,LOW);
     analogWrite(3,HIGH);
     analogWrite(4,LOW);
     analogWrite(5,LOW);
     analogWrite(6,LOW);
     break;
     case 3:
    analogWrite(2,LOW);
     analogWrite(3,LOW);
     analogWrite(4,HIGH);
     analogWrite(5,LOW);
     analogWrite(6,LOW);
     break;
     case 4:
     analogWrite(2,LOW);
     analogWrite(3,LOW);
     analogWrite(4,LOW);
     analogWrite(5,HIGH);
     analogWrite(6,LOW);
     break;
     case 5:
     analogWrite(2,LOW);
     analogWrite(3,LOW);
     analogWrite(4,LOW);
     analogWrite(5,LOW);
     analogWrite(6,HIGH);
     break;
   }
}