#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup(){
  pinMode(3, OUTPUT);
  pinMode(A0, INPUT);
  lcd.init();
  lcd.setCursor(0, 0);
  lcd.backlight();
  lcd.display();
}

void loop(){
  int val = analogRead(A0); 
  val = map(val, 0, 1023, 0, 255);
  analogWrite(3, val);
  int newVal = val * 100 / 255;
  lcd.setCursor(0, 0);
  lcd.print("Led: ");
  lcd.setCursor(4, 0);
  lcd.print(newVal);
  lcd.print("%");
  delay(1000);
  lcd.clear();
}