#include <LiquidCrystal.h>

int n = 0;
LiquidCrystal lcd(8,9,4,5,6,7);

void setup(){
  attachInterrupt(0, count, RISING);
  lcd.begin(16, 2);
}

void loop(){
}

void count(){
  lcd.setCursor(0, 0);
  lcd.print(++n);
}