Write a function which reads, character by character, a hexadecimal number from the standard input and returns the decimal correspondent of the inverted form of the given number. The end of hexadecimal number will be indicated by a blank character. Use this function in a main program to test your function. Examples : Input : b7f2 Output : 12155 (Binary equivalent of 2f7b is 2x16 3 + 15x16 2 + 7x16 1 + 11x16 0 = 12155.)