Question

In the Byteland country a string "S" is said to super ascii string if and only if count of each character in the string is equal
to its ascii value.
In the Byteland country ascii code of 'a' is 1, 'b' is 2 ...'z' is 26.
Any string "S" can be converted to super ascii string by performing operations like addition or removal of a character.
Your task is to find out the minimum number of operations required to convert the string to super ascii string.