DC Motor with potentiometer

const int MotorPin = 3;
const int PotPin = A0;
int PotVal=0;
int Speed=0;




void setup()
{
  pinMode (PotPin, INPUT);
  pinMode (MotorPin, OUTPUT);
  Serial.begin (9600);

}

void loop()
{

  PotVal = analogRead (PotPin);
  Speed = map (PotVal, 0, 1023, 0, 255);
  Speed= constrain (Speed, 0, 255);
  analogWrite (MotorPin, Speed);

}