Delete minimum occurence in a string

[RavCOder]

Hi,
I have to delete minimum number of character in a string.
I saw that there is Counter but I don't know how to use it.
This is my code for now:

word  = "abecedario alpaca"
char = ''
word_list = []
#add a string into a list 
for c in word:
  word_list.append(c)
#print(word_list)
#a counter that check if inside a list there is a char 
count = 0
for counter in word_list: #for any elements of list --> is there char? 
  if counter == char:
    count = count + 1 #counter 

print(count)

This is text :

Given a string s consisting of n lowercase letters, you have to delete the minimum number of characters from s so that every letter in s appears a unique number of times. We only care about the occurrences of letters that appear at least once in result.

Regards,
RavCoder