function solution(record) {
        var nickNames = {};
        record = record.filter((rec) => {
          const [event, id, name] = rec.split(" ");
          name && (nickNames[id] = name);
          return event !== "Change";
        });
    
        return record.map((rec) =>
          rec[0] === "E"
            ? `${nickNames[rec.split(" ")[1]]}님이 들어왔습니다.`
            : `${nickNames[rec.split(" ")[1]]}님이 나갔습니다.`
        );
      }