#E. JIXMPII5J0xMSjV#<^.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ` a b c d e f g h i j k l m n

传统题

2000ms

256MiB

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Statement

In the city of Saint Petersburg, a day lasts for $2^{100}$ minutes. From the main station of Saint Petersburg, a train departs after $1$ minute, $4$ minutes, $16$ minutes, and so on; in other words, the train departs at time $4^k$ for each integer $k \geq 0$ . Team BowWow has arrived at the station at the time $s$ and it is trying to count how many trains have they missed; in other words, the number of trains that have departed strictly before time $s$ . For example if $s = 20$ , then they missed trains which have departed at $1$ , $4$ and $16$ . As you are the only one who knows the time, help them!

Note that the number $s$ will be given you in a binary representation without leading zeroes.

Format

Input

The first line contains a single binary number $s$ ( $0 \leq s < 2^{100}$ ) without leading zeroes.

Output

Output a single number — the number of trains which have departed strictly before the time $s$ .

Sample

100000000

ShanghaiTech ACM 炸鱼杯

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规则: OI
题目: 46
开始于: 2024-12-10 23:00
结束于: 2024-12-15 13:00
持续时间: 110 小时
主持人: _Arahc_
参赛人数: 112

#E. JIXMPII5J0xMSjV#<^.

JIXMPII5J0xMSjV#<^.

Statement

Format

Input

Output

Sample

ShanghaiTech ACM 炸鱼杯

状态

开发

支持

#E. JIXMPII5J0xMSjV#<^.

JIXMPII5J0xMSjV#<^.

Statement

Format

Input

Output

Sample

ShanghaiTech ACM 炸鱼杯

状态

开发

支持

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