#define flagPin1 20

long count1 = 0;

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, Raspberry Pi Pico!");
  pinMode(flagPin1, OUTPUT);
}

void setup1() {
  pinMode(flagPin1, INPUT);
}

void loop() {
  digitalWrite(flagPin1, HIGH);
  Serial.println(count1);
  digitalWrite(flagPin1, LOW);
  delay(25); // this speeds up the simulation
}

void loop1() {
  if (digitalRead(flagPin1) == LOW) {
    count1++;
  }
}