Please solve the below question in R$-$ Write a function that, given a string S encoding a decimal integer $,$ returns a string representing the HexSpeak representation of if is a valid HexSpeak word, or else $$ERROR$.$ A decimal number can be converted to HexSpeak by first converting it to hexadecimal $($in upper case$),$ then converting the number $0$ to the letter $$O$$ and the number $1$ to the letter $$I$.$ A string is considered a valid HexSpeak word if it consists of only the letters ABCDEFIO. The input string will represent a decimal integer between $1$ and inclusive. Examples: If the input string is $257,$ the decimal number it encodes is $257$ which is written as $101$ in hexadecimal. Since $1$ and $0$ represent $$I$$ and $$O$,$ respectively, we should return $$IOI$.$ If the input string is $"3",$ it is written as $3$ in hexadecimal, which does not represent a HexSpeak letter, so we return $$ERROR$.$