입력 출력 예제는 맞는데, 자꾸 오답이레요.

왜죠?

import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    String input = in.next();
    System.out.println(new Main().solution(input));
  }

  private String solution(String input) {
    Map<Character, Integer> map = new HashMap<>();
    Set<Character> keySet = new LinkedHashSet<>();

    for (int i = 0; i < input.length(); i++) {
      keySet.add(input.charAt(i));
      map.put(input.charAt(i), map.getOrDefault(input.charAt(i), 0) + 1);
    }

    StringBuilder sb = new StringBuilder();
    keySet.forEach(character -> {
      if (map.get(character) > 1) {
        sb.append(character).append(map.get(character));
      } else {
        sb.append(character);
      }
    });

    return String.valueOf(sb);
  }
}