const int redBtn = 2;  
const int blueBtn = 4;  
const int greenLed = 13;     

void setup() {
//Button Setup
pinMode(blueBtn, INPUT);
pinMode(redBtn, INPUT);
//Led Setup
pinMode(greenLed, OUTPUT);
}

void loop() {

  int blueBtnState=digitalRead(blueBtn);
  int redBtnState=digitalRead(redBtn);

  if (blueBtnState == LOW && redBtnState == HIGH) {
    
    digitalWrite(greenLed, HIGH);
  } else if (blueBtnState == HIGH && redBtnState == LOW) {
 
    digitalWrite(greenLed, HIGH);
  } else {
    digitalWrite(greenLed, LOW);
  }
}