{"problem":{"name":"Reverse and Minimize","description":{"content":"For a positive integer $x$, let $f(x)$ be the answer to the question below. > The following operation on $x$ can be performed zero or more times. >  > *   Let $x'$ be the integer obtained by reversin","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"arc142_a"},"statements":[{"statement_type":"Markdown","content":"For a positive integer $x$, let $f(x)$ be the answer to the question below.\n\n> The following operation on $x$ can be performed zero or more times.\n> \n> *   Let $x'$ be the integer obtained by reversing the decimal notation of $x$. Then, replace $x$ with $x'$. If $x$ now has one or more leading zeros, delete them so that it begins with a non-zero digit.\n> \n> For example, from $x=1420$, you get $x=241$ after one operation, $x=142$ after two operations, and $x=241$ after three operations.  \n> Find the minimum possible value of $x$ after operations.\n\nFind the number of integers $x$ such that $1 \\leq x \\leq N$ and $f(x)=K$.\n\n## Constraints\n\n*   $1 \\leq N,K \\leq 10^{12}$\n*   All values in input are integers.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$ $K$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"arc142_a","tags":[],"sample_group":[["1420 142","3\n\nThree integers $x=142$, $241$, and $1420$ satisfy $1 \\leq x \\leq 1420$ and $f(x)=142$."],["1419 142","2"],["6 19","0"]],"created_at":"2026-03-03 11:01:14"}}