void setup() {
  pinMode(8, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(4, OUTPUT);

  pinMode(A0, INPUT_PULLUP);
  pinMode(A3, INPUT_PULLUP);
  pinMode(A5, INPUT_PULLUP);

}

void loop() {
  if(digitalRead(A0)==0){
    digitalWrite(8, HIGH);
  }
  if(digitalRead(A3)==0){
    digitalWrite(6, HIGH);
  }
  if(digitalRead(A5)==0){
    digitalWrite(4, HIGH);
  }
  else{
    digitalWrite(8, LOW);
    digitalWrite(6, LOW);
    digitalWrite(4, LOW);
  }
}