#include <LiquidCrystal.h>
LiquidCrystal lcd(12,13,14,15,16,17);
void setup() {
lcd.begin(16,2);
Serial.begin(9600);
Serial.println("enter input (on/off):");
pinMode(18,OUTPUT);
}

void loop() {
if(Serial.available()>0){
  String x=Serial.readStringUntil('\n');
  if(x=="On"||x=="on")
  {
    //lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("LED"+x);
    digitalWrite(18,HIGH);
    delay(2000);
    }
    else if (x=="off"||x=="Off")
    {
      //lcd.clear();
      lcd.setCursor(0,0);
      digitalWrite(18,LOW);
      lcd.print("LED"+x);
      delay(2000);
    }
}
}