Задача 8

inp = input()
result = 0
n = 0
nprev = 0

while inp != ".":
    if inp == "I":
        n = 1
    elif inp == "V":
        n = 5
    elif inp == "X":
        n = 10
    elif inp == "L":
        n = 50
    elif inp == "C":
        n = 100
    elif inp == "D":
        n = 500
    elif inp == "M":
        n = 10000
    else:
        print("Invalid symbol")
        break
    result += n
    if nprev < n:
        result -= 2*nprev
    nprev = n
    inp = input()

if result != 0:
    print(result)