volatile bool triggered;

#define MAKE_HANDLER(pin) \
  volatile int count_##pin; \
  void handler_##pin() \
  { \
    ++count_##pin; \
    triggered = true; \
  }

MAKE_HANDLER(16)
MAKE_HANDLER(17)
MAKE_HANDLER(18)

void setup() {
  Serial.begin(0);
  attachInterrupt(digitalPinToInterrupt(16), handler_16, RISING);
  attachInterrupt(digitalPinToInterrupt(17), handler_17, RISING);
  attachInterrupt(digitalPinToInterrupt(18), handler_18, RISING);
}

void loop() {
  if (!triggered)
    return;

  Serial.println(String() + count_16 + " " + count_17 + " " + count_18);
  triggered = false;
}