#include <Servo.h>

Servo myservo;
int buttonPin = 4;          
int buttonState;              
int lastButtonState = HIGH;  
bool isAt180 = false;        

void setup() {
  myservo.attach(9);               
  myservo.write(0);              
  pinMode(buttonPin, INPUT_PULLUP); 
}

void loop() {
  buttonState = digitalRead(buttonPin); 

  
  if (buttonState == LOW && lastButtonState == HIGH) {
    if (isAt180) {
      
      myservo.write(0);
      isAt180 = false;
    } else {
     
      myservo.write(180);
      isAt180 = true;
    }

    delay(200); 
  }

  lastButtonState = buttonState; 
}