int bt1=11;
int bt2=9;
int led=3,dt=500,bright=0;
int buz=5,bthigh,btlow;
void setup(){
  pinMode(bt1,INPUT);
    pinMode(bt2,INPUT);
  pinMode(led,OUTPUT);
    pinMode(buz,OUTPUT);
  Serial.begin(9600);
}
void loop(){
  bthigh=digitalRead(bt1);
    btlow=digitalRead(bt2);
Serial.print("Button 1=");
  Serial.print(bthigh);
Serial.print("Button 2=");
  Serial.println(btlow);
  delay(dt);
  if(bthigh==0){
   bright=bright+5; 
  }
  if(btlow==0){
   bright=bright-5; 
  }
  if(bright>255){
   bright=255; 
  }
  if(bright<0){
   bright=0; 
  }
  analogWrite(led,bright);
}