Sanalista

import java.util.*;

class Problem {
    public static void main(String args[]) {
        Scanner input = new Scanner(System.in);

        int words_amount = input.nextInt();
        int wweaol = 0;
        List<String> checked_chars = new ArrayList<String>();

        for (int i=0; i<words_amount; i++) {
            String current_word = input.next();
            boolean even_amount = false;

            if (current_word.length() % 2 == 0) {
                for (int j=0; j<current_word.length(); j++) {
                    char current_character = current_word.charAt(j);
                    int chars_found = 0;

                    for (int k=j++; k<current_word.length(); k++) {
                        if (current_word.charAt(k) == current_character)
                            chars_found++;
                    }

                    if (chars_found % 2 == 0) {
                        even_amount = true;
                    }
                }

                if (even_amount) {
                    wweaol++;
                }
            }      
        }

        System.out.println(wweaol);
    }
}

Test 1

Verdict: RUNTIME ERROR

Error: Could not find or load main class problem
Caused by: java.lang.ClassNotFoundException: problem

Test 2

Verdict: RUNTIME ERROR

Error: Could not find or load main class problem
Caused by: java.lang.ClassNotFoundException: problem

Test 3

Verdict: RUNTIME ERROR

Error: Could not find or load main class problem
Caused by: java.lang.ClassNotFoundException: problem