문제
싱글벙글 즐거운 UDPC 수학 수업 시간. 포닉스는 아래와 같은 내용을 배웠다.
- 음이 아닌 정수 $P$에 대해, $P$의 숫자들을 거꾸로 읽어도 원래의 $P$와 같다면 $P$을 팰린드롬 수라고 한다. (단, 여러 자릿수로 구성된 수는 0ドル$으로 시작할 수 없다.)
예를 들어 111ドル,ドル 1771ドル$은 팰린드롬 수이지만, 100ドル$은 팰린드롬 수가 아니다.
수업이 끝난 후, 포닉스는 팰린드롬 수라는 개념이 너무 재미없다고 생각했고, 집에서 포린드롬 수라는 새로운 수를 만들었다. 포닉스의 포린드롬 수는 아래와 같이 정의된다.
- 음이 아닌 정수 $P$에 대해, $P$와 $\lfloor {P \over 10} \rfloor$이 모두 팰린드롬 수일 때, $P$을 포린드롬 수라고 정의한다.
포닉스는 자신이 만든 수가 너무 아름답다고 느낀 나머지, 자신의 우월함을 뽐내기 위해 달구와 윤이에게 "주어진 $N$에 대해, $N$보다 작거나 같은 포린드롬 수의 개수를 구해봐!" 라고 문제를 냈다. 달구와 윤이를 도와 문제를 풀고, 포닉스의 코를 납작하게 해주자!
출력
$N$보다 작거나 같은 포린드롬 수의 개수를 출력한다.
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