if isMainIsland == True:
    if itemCategory == "book":
        if price >= 1500:
            charge = 0
        else:
            charge = 400
    else:
        charge = 500
else:
    if itemCategory == "book":
        if price >= 1500:
            charge = 300
        else:
            charge = 400 #Can't detect even if the value is wrong
    else:
        charge = 1000