# 打印 1 ~ 10
# num = 1
# while num < 11:
#     print(num)
#     num += 1

# 计算 1 ~ 100 的和
# num = 1
# sum = 0
# while num < 101:
#     sum += num
#     num += 1
# print(sum)
#
# sum = int((1 + 100) * 100 / 2)
# print(sum)

# 计算 5!
# num = 1
# sum = 1
# while num < 6:
#     sum *= num
#     num += 1
# print(sum)

# 计算 1! + 2! + ... + 5!
num = 1
temp = 1
ret = 0
while num < 6:
    ret += temp
    num += 1
    temp *= num
print(ret)