{"problem":{"name":"Adjacent Chmax","description":{"content":"You are given a permutation $P=(P_1,P_2,\\cdots,P_N)$ of $(1,2,\\cdots,N)$. You may perform the following operation zero or more times. *   Choose an integer $i$ ($1 \\leq i \\leq N-1$). Let $v=\\max(P_i,","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"agc058_b"},"statements":[{"statement_type":"Markdown","content":"You are given a permutation $P=(P_1,P_2,\\cdots,P_N)$ of $(1,2,\\cdots,N)$.\nYou may perform the following operation zero or more times.\n\n*   Choose an integer $i$ ($1 \\leq i \\leq N-1$). Let $v=\\max(P_i,P_{i+1})$ and replace the values of $P_i$ and $P_{i+1}$ with $v$.\n\nHow many sequences are there that $P$ can be after your operations? Find the count modulo $998244353$.\n\n## Constraints\n\n*   $2 \\leq N \\leq 5000$\n*   $(P_1,P_2,\\cdots,P_N)$ is a permutation of $(1,2,\\cdots,N)$.\n*   All values in input are integers.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$\n$P_1$ $P_2$ $\\cdots$ $P_N$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"agc058_b","tags":[],"sample_group":[["3\n1 3 2","4\n\nThe four sequences that $P$ can become are $(1,3,2)$, $(3,3,2)$, $(1,3,3)$, and $(3,3,3)$."],["4\n2 1 3 4","11"],["10\n4 9 6 3 8 10 1 2 7 5","855"]],"created_at":"2026-03-03 11:01:14"}}