int led=9;
int counter=0;
void setup() {
  // put your setup code here, to run once:
  pinMode(led,OUTPUT);
  digitalWrite(led,HIGH);
}

void loop() {
  // put your main code here, to run repeatedly:
  int val= analogRead(A0);
  val=map(val,0,1023,0,255);
  if (counter%3==0){
    val=min(255,val+100);
    analogWrite(led,val);}
  else{
  analogWrite(led,val-50);
  }
  counter+=1;
  Serial.println(val);
  delay(1000);
}