const int ledPin = 0;
const int buttonPin = 1;

int buttonState = 0;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLDOWN);
}

void loop() {
  buttonState = digitalRead(buttonPin);
  
  if(buttonState == HIGH) {
    digitalWrite(ledPin, !digitalRead(ledPin));
    delay(1000);
  }
}