#include <Servo.h>

Servo myservo;

int value = 0;

void setup() {
  // put your setup code here, to run once:
  myservo.attach(11);
  pinMode(A4, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  value = analogRead(A4);
  value = map(value, 0, 1023, 0, 180);
  myservo.write(value);
  delay(100);
}