Blinking while changing brightness of led

int pin=9;
int brightness1=5;
int brightness2=100;
int brightness3=255;
int del=500;
void setup() {
  // put your setup code here, to run once:
pinMode(pin,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
analogWrite(pin,brightness1);
delay(del);
analogWrite(pin,brightness2);
delay(del);
analogWrite(pin,brightness3);
delay(del);
}