#include <Servo.h>
Servo myServo;
int pos = 0;

void setup() {
  // put your setup code here, to run once:
  myServo.attach(6);
  pinMode(13, INPUT_PULLUP);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  myServo.write(0);
  if(digitalRead(13) == HIGH){
    pos++;
    while(digitalRead(13) == HIGH){
      delay(50);
    }
  }
  if(pos > 2){
    pos = 0;
  }

  Serial.println(pos);

  if(pos == 1){
    myServo.write(180);
    delay(500);
  }else if(pos == 2){
    myServo.write(90);
    delay(500);
  }else if(pos == 0){
    myServo.write(0);
  }
}