#include <LiquidCrystal_I2C.h> //

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  pinMode(A0, INPUT);
  pinMode(3, OUTPUT);
  Serial.begin(9600);
  lcd.begin(16,2);
  lcd.init();
  lcd.backlight();
}

void loop() {
  int a = analogRead(A0);
  int pwm = map(a,0,1023,0,100);
  analogWrite(3, pwm);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(pwm);
  lcd.print("%");

  delay(250);
}