Recently, Anton has found a set. The set consists of small English letters. Anton carefully wrote out all the letters from the set in one line, separated by a comma. He also added an opening curved bracket at the beginning of the line and a closing curved bracket at the end of the line. 

Unfortunately, from time to time Anton would forget writing some letter and write it again. He asks you to count the total number of distinct letters in his set.
The first and the single line contains the set of letters. The length of the line doesn't exceed 1000. It is guaranteed that the line starts from an opening curved bracket and ends with a closing curved bracket. Between them, small English letters are listed, separated by a comma. Each comma is followed by a space.
# Read the input line
line = input()

# Remove the opening and closing brackets
line = line[1:-1]

# Split the line into individual letters
letters = line.split(", ")

# Remove leading/trailing whitespace from each letter
letters = [letter.strip() for letter in letters]

# Convert the list to a set to remove duplicates
distinct_letters = set(letters)

# Get the number of distinct letters
num_distinct = len(distinct_letters)

# If the set is empty, set the number of distinct letters to 0
if num_distinct == 1 and list(distinct_letters)[0] == '':
    num_distinct = 0

# Print the result
print(num_distinct)
