Java - 백준 코딩테스트 1110번 [while문 - 더하기 사이클]

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
 
public class PlusCycle {
 
    public static void main(String[] args) throws IOException {
        // 20210618 - 1110번
        //===============================================================다시 풀기
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        
        int num = Integer.parseInt(br.readLine());
        int newNum = num;
        int count = 0;
        
        while(true) {
            num = (num % 10) * 10 + ((num / 10) + (num % 10)) % 10;
            count++;
            if (num == newNum) {
                break;
            }
        }
        
        bw.write(String.valueOf(count));
        bw.flush();
        br.close();
        bw.close();
    }
}