#define led 3
const char* KODA = "4264";

void setup() {
  Serial.begin(115200);
  Serial.println("Ce hoces prizgati ledico vpisi 4264");
  pinMode(led, OUTPUT);

}

void loop() {
  if(Serial.available()){
    char input[strlen(KODA)];
    Serial.readBytes(input, strlen(KODA));
    input[strlen(KODA)] = '\0'; 
    if(strcmp(input, KODA) == 0){
      digitalWrite(led, HIGH);
      Serial.println("Ledica prizgana");
      delay(200);
    }
    else{
      digitalWrite(led, LOW);
      Serial.println("Ledica prizgana");
      delay(200);
    }
  while (Serial.available() > 0) {
    Serial.read();
  }  
}
}