int sw1=5;
int sw2=6;
int sw3=9;
int sw4=10;
int sw5=11;
String a;
#include<LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);
void setup() {
  pinMode(sw1, INPUT);
  pinMode(sw2, INPUT);
  pinMode(sw3, INPUT);
  pinMode(sw4, INPUT);
  pinMode(sw5, INPUT);
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.print("Enter a password");
  delay(1000);

  // put your setup code here, to run once:

}

void loop() {
  int push1=digitalRead(sw1);
  int push2=digitalRead(sw2);
  int push3=digitalRead(sw3);
  int push4=digitalRead(sw4);
  int push5=digitalRead(sw5);
  if (push1 == 1)
  {
    a += "1";
    delay(1000);
    Serial.println(a);
  }
  if (push2 == 1)
  {
    a +="2";
    delay(1000);
    Serial.println(a);
  }
  if (push4 == 1)
  {
    a +="3";
    delay(1000);
    Serial.println(a);
  }
  if (push5 == 1)
  {
    a +="4";
    delay(1000);
    Serial.println(a);
  }
      if(a.length()>=4)
      {
  
  if (a == "1234")
  {
    
    Serial.println(a);
    Serial.println(a.length());
    lcd.clear();
    lcd.print("correct password");
    delay(1000);
    lcd.clear();
  }
   
    else 
  {
    
    Serial.println(a);
    Serial.println(a.length());
    lcd.clear();
    lcd.print("incorrect password");
    delay(1000);
    lcd.clear();
  }
  }
}