const int ledPin1 = 12;
const int ledPin2 = 13;
const int buttonPin = 4;
int buttonState = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);

}

void loop() {
  // put your main code here, to run repeatedly:
  buttonState = digitalRead(buttonPin);
  if (buttonState == LOW) {
    delay(100);
    digitalWrite(ledPin1, HIGH);
    digitalWrite(ledPin2, LOW);
    Serial.println("LED1 ON");
  }
  else {
    delay(100);
    digitalWrite(ledPin2, HIGH);
    digitalWrite(ledPin1, LOW);
    Serial.println("LED2 ON");
  }

}