void setup() {
  pinMode(4, INPUT);
  pinMode(5, INPUT);
  pinMode(3, OUTPUT);
}

void loop() {
  if (digitalRead(4) == HIGH && digitalRead(5) == HIGH) {
    digitalWrite(3, LOW);
    delay(200);
    digitalWrite(3, HIGH);
    delay(200);
  } 
  else {
    digitalWrite(3, HIGH);
  }
}