const int rled (13);
const int bled (12);
const int gled (11);
const int but (2);


void setup() {
pinMode(rled, OUTPUT);
pinMode(bled, OUTPUT);
pinMode(gled, OUTPUT);
pinMode(but, INPUT_PULLUP);

}

void loop() {
if (digitalRead(but) == LOW) {

int randomled = random(3);

if (randomled == 0)
    {digitalWrite(rled, HIGH);
      delay(500);
        digitalWrite(rled, LOW);}
if (randomled == 1)
    {digitalWrite(bled, HIGH);
      delay(500);
        digitalWrite(bled, LOW);}
if (randomled == 2)
    {digitalWrite(gled, HIGH);
      delay(500);
        digitalWrite(gled, LOW);}
}



else {digitalWrite(rled, LOW);
      digitalWrite(bled, LOW);
      digitalWrite(gled, LOW);}
}