#include <LiquidCrystal_I2C.h>


LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  // put your setup code here, to run once:
lcd.init();
lcd.backlight();

Serial.begin(9600);

}

void loop() {
  // put your main code here, to run repeatedly:

int pocet = random(1, 21);
lcd.clear();

for (int i = 0; i <pocet; i++) {
  int x = random(0, 20);
  int y = random(0, 4);
  lcd.setCursor(x, y);
  lcd.print("X");
  
}
Serial.println(pocet);
delay(1000);
}