int leds[]    = {4, 6}; // LED pins
int buttons[] = {2, 3}; // Button pins

void setup() 
{
  for (int i = 0; i < 2; i++) 
  {
    pinMode(leds[i], OUTPUT);
    pinMode(buttons[i], INPUT_PULLUP);
  }

  attachInterrupt(digitalPinToInterrupt(buttons[0]), handleButtonPress0, FALLING);
  attachInterrupt(digitalPinToInterrupt(buttons[1]), handleButtonPress1, FALLING);
}

void loop() 
{
  // leer
}

void handleButtonPress0() 
{
  digitalWrite(leds[0], !digitalRead(leds[0])); 
  delay(50); // debounce
}

void handleButtonPress1() 
{
  digitalWrite(leds[1], !digitalRead(leds[1])); 
  delay(50); // debounce
}