784 B | 784 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
d = {"I": 1, "V": 5, "X": 10, "L": 50, "C": 100, "D": 500, "M": 1000}
s = input()
ans = 0
crt = 0
l = []
for i in s:
if '0' <= i <= '9':
crt *= 10
crt += int(i)
else:
l.append([d[i], crt])
crt = 0
for i in range(0, len(l)):
if i + 1 < len(l):
if l[i + 1][0] > l[i][0]:
ans -= l[i][0] * l[i][1]
continue
ans += l[i][0] * l[i][1]
print(ans)
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()