void setup() 
{
  // put your setup code here, to run once:
  pinMode(13, OUTPUT);
  pinMode(10, INPUT);
}

void loop() 
{
  // put your main code here, to run repeatedly:
  int buttonstate = digitalRead(10);
  if (buttonstate == HIGH)
  {
    digitalWrite(13, LOW);
  }
  else 
  {
    digitalWrite(13, HIGH);
  }
}