#include <Wire.h>
#include <LiquidCrystal_I2C.h>
int val;
int ledpin = 13;
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup ()
{
 Serial.begin (9600);
 pinMode (ledpin, OUTPUT);
 lcd.init();
 lcd.print("Hello World!");
 lcd.setCursor(8, 1);
}
void loop ()
{
 val = Serial.read ();
 if (val == 'R') {
 lcd.setCursor(0, 1);
 digitalWrite (ledpin, HIGH);
 delay (500);
 digitalWrite (ledpin, LOW);
 delay (500);
 lcd.print("Hello World!");
 }
}