int greenLED = 13;
int redLED = 18;
int button1 = 12;
int button2 = 17;

void setup() 
{
  pinMode(13, OUTPUT);
  pinMode(18, OUTPUT);
  pinMode(12, INPUT);
  pinMode(17, INPUT);
}
void loop()
{
  int state1 = digitalRead(12);
  int state2 = digitalRead(17);

  if (state1 == HIGH) 
  {
    digitalWrite(13, HIGH);
    digitalWrite(18, LOW);
  }
  else if (state2 == HIGH)
  {
    digitalWrite(18, HIGH);
    digitalWrite(18, LOW);
  }
  else 
  {
    digitalWrite(13, LOW);
    digitalWrite(18, LOW);
  }
}