#include <Servo.h>
Servo myServo;
void setup() {
  // put your setup code here, to run once:
  myServo.attach(9);
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int i=0;i<180;i++){
    myServo.write(i);
    delay(30);
  }
  for(int i=179;i>=0;i--){
    myServo.write(i);
    delay(30);
  }
}