#define button 1 // PA5
#define led 10 // PA3

void setup() {
  // put your setup code here, to run once:
  pinMode(led, OUTPUT);
  pinMode(button, INPUT);
  Serial.begin(9600);
  while(!Serial.available()); // wait for serial
  String retrieve = Serial.readString();
  digitalWrite(led, HIGH);
}

void loop() {
  // put your main code here, to run repeatedly:
  int result = digitalRead(button);
  Serial.println(result); 
  delay(100);
}