const int button = 4;
const int led = 2;
bool ledState = false;
unsigned long lastPress = 0;

void setup() {
  pinMode(button, INPUT_PULLUP);
  pinMode(led, OUTPUT);
}

void loop() {
  if (digitalRead(button) == LOW && millis() - lastPress > 300) {
    ledState = !ledState;
    digitalWrite(led, ledState);
    lastPress = millis();
  }
}