int bsr=0;
int bsg=0;
int bsb=0;

void setup() {

pinMode(21, OUTPUT);
pinMode(17,OUTPUT);
pinMode(16,OUTPUT);

pinMode(15, INPUT);
pinMode(2, INPUT);
pinMode(0, INPUT);

}

void loop() {

bsr = digitalRead(15);
bsb = digitalRead(2);
bsg = digitalRead(0);


digitalWrite(21, (1-bsg));
digitalWrite(17, (1-bsr));
digitalWrite(16, (1-bsb));

}