a044. 空間切割 -- 許介彥 | From: [210.243.21.253] | 發表日期 : 2023-05-08 20:48

try :
    while True:
        n = int(input())
        space = ((n+1)*((n*n)-n+6))/6
        print('%d' % (space))
except EOFError:
    pass