#define LED1 2
#define LED2 3
#define LED3 4
#define BUTTON 12

unsigned long PreviousMillis;


void setup() {
  
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(BUTTON, INPUT);

}

void loop() {
  
  unsigned long CurrentMillis = millis();

  if ((unsigned long) CurrentMillis - PreviousMillis >= 1000){

     digitalWrite(LED1, HIGH);
     digitalWrite(LED2, LOW);

  }

  if ((unsigned long) CurrentMillis - PreviousMillis >= 2000){

     digitalWrite(LED1, LOW);
     digitalWrite(LED2, HIGH);

    PreviousMillis = CurrentMillis;

  }

  if (digitalRead(BUTTON) == HIGH){

digitalWrite(LED3, HIGH);    

  }else {

digitalWrite(LED3, LOW);

  }

}