const int but = 30; 
const int led = 31; 


int bs = 0; 
int vbs = 0; 

void setup() 
{
pinMode(led, OUTPUT);
pinMode(but, INPUT_PULLUP);

}

void loop()
{
bs = digitalRead(but);

  if (bs == LOW)
    {
      // turn LED on:
      vbs = !vbs;
      delay(300);
    }
  else 
  {
  if (vbs == HIGH)
  {
    // turn led on
    digitalWrite(led, HIGH);
  }
  else 
    {
    // turn LED off:
      digitalWrite(led, LOW);
  
    }
  }
}