问题 1014: [编程入门]阶乘求和)：（本地测试正确；但提交不对！！？？）求教

# 10014：阶乘求和
# Sn = 1! + 2! + 3! +...+n!
def factorial_cal(n):
    ‘‘‘
    cal n!
    ‘‘‘
    sum_t = 1
    while n>1:
        sum_t = sum_t * n
        n = n-1
    return sum_t

if __name__ == ‘__main__‘:
    n = int(input())
    sum = 0
    if n>=0 & n<=20:
        while n>0:
            sum_temp = factorial_cal(n)
            sum = sum + sum_temp
            n=n-1
        print (sum)