// add more LEDs if required 
constexpr byte LedPins[] {8,9,10,11,12}; 
constexpr byte ButtonPin {A0}; 
void setup() {
  for (auto LedPin:LedPins) pinMode(LedPin,OUTPUT); 
  pinMode(ButtonPin,INPUT_PULLUP);
  
}


void loop() {
  if (digitalRead(ButtonPin)) {    
    for (auto LedPin:LedPins) digitalWrite(LedPin,LOW); 
    digitalWrite (LedPins[random(0,sizeof(LedPins))],HIGH); 
    delay (50);
  }
}