#include <keypad>

void setup() {
  // put your setup code here, to run once:
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
  Serial.println("Iniciando...");
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
  delay(500);
  Serial.println(LED_BUILTIN);
}