#include<Servo.h>
Servo myservo;

void setup() {
  // put your setup code here, to run once:
myservo.attach(9);
myservo.write(0);
}

void loop() {

for(int i=0; i<=180; i++){  
myservo.write(i);
delay(15);
}

for(int j =180; j>=0; j--){
myservo.write(j);
delay(15);
}
}