while True: try: num = eval(input()) if num: # print(num // 3 +(num // 3 + num % 3)//2) print(num //2) else: break except: break
while True: try: num = eval(input()) if num: # print(num // 3 +(num // 3 + num % 3)//2) print(num //2) else: break except: break