Python bmi calcultor

wrote a quick bmi calculator for imperial and metric it might not be perfect but i wanna know how can i make it better

m_or_i = int(input("Enter 1 for metric and 2 for imperial: "))

if m_or_i == 1:
    h1 = float(input("Enter your height in cm: "))
    h = h1 / 100
    w = float(input("Enter your weight in kgs: "))
    an = w / h ** 2
    if an < 18.4:
        print"Your bmi is:", (round(an, 1)), "which means you are under weight"
    elif 18.5 <= an <= 24.9:
        print"Your bmi is:", (round(an, 1)), "which means you are normal weight"
    elif 25 <= an <= 29.9:
        print"Your bmi is:", (round(an, 1)), "which means you are over weight"
    elif 30 <= an <= 34.9:
        print"Your bmi is:", (round(an, 1)), "which means you are obese class 1"
    elif 35 <= an <= 39.9:
        print"Your bmi is:", (round(an, 1)), "which means you are obese class 2"
    elif an >= 40:
        print"Your bmi is:", (round(an, 1)), "which means you are obese class 3"

elif m_or_i == 2:
    h1 = float(input("Enter your height in feet: "))
    h2 = float(input("Enter the inches: "))
    h = h1 * 12 + h2
    w = float(input("Enter your weight in pounds: "))
    an = w * 703 / h ** 2
    if an < 18.4:
        print"Your bmi is:", (round(an, 1)), "which means you are under weight"
    elif 18.5 <= an <= 24.9:
        print"Your bmi is:", (round(an, 1)), "which means you are normal weight"
    elif 25 <= an <= 29.9:
        print"Your bmi is:", (round(an, 1)), "which means you are over weight"
    elif 30 <= an <= 34.9:
        print"Your bmi is:", (round(an, 1)), "which means you are obese class 1"
    elif 35 <= an <= 39.9:
        print"Your bmi is:", (round(an, 1)), "which means you are obese class 2"
    elif an >= 40:
        print"Your bmi is:", (round(an, 1)), "which means you are obese class 3"