{"raw_statement":[{"iden":"problem statement","content":"Given is an integer $N$.  \nHow many integers $x$ between $1$ and $N$ (inclusive) satisfy the following condition?\n\n*   The decimal representation (without leading zeros) of $x$ has an even number of digits, and its first and second halves are equal as strings."},{"iden":"constraints","content":"*   $N$ is an integer.\n*   $1 ≤ N < 10^{12}$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$"},{"iden":"sample input 1","content":"33"},{"iden":"sample output 1","content":"3\n\nThree numbers $11$, $22$, and $33$ satisfy the condition."},{"iden":"sample input 2","content":"1333"},{"iden":"sample output 2","content":"13\n\nFor example, the decimal representation of $1313$ has four digits, and its first and second halves are both $13$, so $1313$ satisfies the condition."},{"iden":"sample input 3","content":"10000000"},{"iden":"sample output 3","content":"999"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}