Roman numerals use seven symbols: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000.
Symbols are usually written from largest to smallest and added together. When a smaller symbol comes right before a larger one, it is subtracted instead: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400 and CM = 900.
Given a valid Roman numeral s, return its value.
Examples
Example 1
- Input
- s = "III"
- Output
- 3
Example 2
- Input
- s = "LVIII"
- Output
- 58
- Why
- L = 50, V = 5, III = 3.
Example 3
- Input
- s = "MCMXCIV"
- Output
- 1994
- Why
- M = 1000, CM = 900, XC = 90, IV = 4.
Constraints
1 <= s.length <= 15sis a valid Roman numeral between 1 and 3999.