代码：

height = input("身高：")
weight = input("体重：")
h = float(height)
w = float(weight)
BMI = w/(h**2)
if BMI < 18.5:
    print ("过轻")
elif BMI < 25:
    print("正常")
elif BMI < 28:
    print("过重")
elif BMI < 32:
    print("肥胖")
else:
    print("严重肥胖")