#include <LiquidCrystal.h>

const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

String a = "0";

void setup() {
  lcd.begin(16, 2);
  Serial.begin(9600);
  Serial.println("Vnesi eno od vrednosti da se zgodi zeleno");
  lcd.setCursor(2, 2);
  lcd.print(a);
}

void loop() {
  if (Serial.available()) {
    char podatek = Serial.read();
    int vnos = podatek - '0'; 

    if (vnos == 1) {  
      int b = a.toInt();  
      b++;
      a = String(b);
      lcd.clear();
      lcd.setCursor(2, 2);
      lcd.print(a);
    }
  }
}