#include <stdio.h>
#include <stdlib.h>

void setup() {
  // put your setup code here, to run once:
  Serial1.begin(115200);
  Serial1.println("hello");
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(1); // this speeds up the simulation
  auto button = digitalRead(2);
  if (button < 0 || button > 9) {
    Serial1.println("bad");
    return;
  }
  char a = '0' + button;
  Serial1.println(a);
  if (button)
    digitalWrite(0, 1);
}