code to covert temperature to celsius and vice versa

print("convert temperature from celsius to fahrenheit or vice versa")
while True:
    ch=int(input("pick your choice \n 1.celsius to fahrenheit \n 2.fahrenheit to celsius\n"))
    if ch==1:
        a=float(input("enter temp in celsius"))
        b=a*1.8+32
        print(a,"degree celsius in fahrenheit is",b)
    elif ch==2:
        c=float(input("enter temp in fahrenheit"))
        d=((c-32)*5)/9
        print(c,"degree fahreneheit in celsius is",d)