void setup() {
  // put your setup code here, to run once:

pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(6, INPUT_PULLUP); //utilizamor resisencias internas del arduino

}

void loop() {
  // put your main code here, to run repeatedly:

if(digitalRead (6)==LOW){

digitalWrite(2, HIGH);
digitalWrite(3, LOW);
digitalWrite(4, LOW);
}

else { // de lo contrario
digitalWrite(2, LOW);
digitalWrite(3, HIGH);
digitalWrite(4, HIGH);
}
}