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Roman to Integer

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Roman to Integer

easy

Roman to Integer

Hash Table
Math
String

Roman numerals write numbers with seven letters, each worth a fixed amount:

I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000.

A numeral is normally read by adding up its letters, which run from the largest value to the smallest: CLX is 100 + 50 + 10 = 160. The exception is six fixed pairs where a smaller letter stands in front of a larger one. Then the smaller one is taken away instead of added:

IV = 4 and IX = 9
XL = 40 and XC = 90
CD = 400 and CM = 900

Given the numeral s, return the whole number it stands for.

Examples

Example 1

Input

s

V

I

I

I

Output

8

Explain:

V is 5, and each of the three Is after it adds 1.

Example 2

Input

s

X

L

I

I

Output

42

Explain:

X comes before the larger L, so together they make 40. The two Is add 2.

Example 3

Input

s

M

M

C

D

X

C

I

V

Output

2494

Explain:

MM is 2000, CD is 400, XC is 90 and IV is 4.

Constraints

1 <= s.length <= 15
s uses only the letters I, V, X, L, C, D and M.
s is the standard way of writing a whole number from 1 to 3999: largest values first, with subtraction only through the six pairs above. Forms like IIII, VX or IC never appear.

Stuck? Hint 1

Each letter is added, except when a smaller letter sits right before a larger one: then it is subtracted.

Input

V

I

I

I

Expected Output

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