int flamePin = 2;
int smokePin = 3;
int relePin = 12;

void setup() {
pinMode(flamePin, INPUT );
pinMode(smokePin, INPUT );
pinMode(relePin, OUTPUT);
}

void loop() {
  int flame = digitalRead(flamePin);
  int smoke = digitalRead(smokePin);
  bool fire = flame||smoke;
  digitalWrite(relePin,fire);
}