Given a string, find the number of different characters in it.

Example

For s = "cabca", the output should be

solution(s) = 3.

There are 3 different characters a, b and c.

Input/Output

• [execution time limit] 3 seconds (java)

• [memory limit] 1 GB

• [input] string s

  A string of lowercase English letters.

  Guaranteed constraints:

  3 ≤ s.length ≤ 1000.

• [output] integer

풀이

int solution(String s) {
    HashSet <Character> set = new HashSet<>();
    
    for (char c : s.toCharArray()) {
        set.add(c);
    }
    
    return set.size();
}