#define BUTTON_ON 1
#define BUTTON_OFF 2
#define LED 3

boolean ledState = HIGH;

void lightOn() {
  ledState = LOW;
}

void lightOff() {
  ledState = HIGH;
}

void setup() {
  pinMode(BUTTON_ON, INPUT);
  pinMode(BUTTON_OFF, INPUT);
  pinMode(LED, OUTPUT);
  attachInterrupt(digitalPinToInterrupt(BUTTON_ON), 
    lightOn, RISING);
  attachInterrupt(digitalPinToInterrupt(BUTTON_OFF), 
    lightOff, RISING);
  digitalWrite(LED, LOW);
}

void loop() {
  digitalWrite(LED, ledState);
}