{"raw_statement":[{"iden":"problem statement","content":"Let $N$ be a positive even number.\nWe have a permutation of $(1, 2, ..., N)$, $p = (p_1, p_2, ..., p_N)$. Snuke is constructing another permutation of $(1, 2, ..., N)$, $q$, following the procedure below.\nFirst, let $q$ be an empty sequence. Then, perform the following operation until $p$ becomes empty:\n\n*   Select two adjacent elements in $p$, and call them $x$ and $y$ in order. Remove $x$ and $y$ from $p$ (reducing the length of $p$ by $2$), and insert $x$ and $y$, preserving the original order, at the beginning of $q$.\n\nWhen $p$ becomes empty, $q$ will be a permutation of $(1, 2, ..., N)$.\nFind the lexicographically smallest permutation that can be obtained as $q$."},{"iden":"constraints","content":"*   $N$ is an even number.\n*   $2 ≤ N ≤ 2 × 10^5$\n*   $p$ is a permutation of $(1, 2, ..., N)$."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$p_1$ $p_2$ $...$ $p_N$"},{"iden":"sample input 1","content":"4\n3 2 4 1"},{"iden":"sample output 1","content":"3 1 2 4\n\nThe solution above is obtained as follows:\n\n$p$\n\n$q$\n\n$(3, 2, 4, 1)$\n\n$()$\n\n↓\n\n↓\n\n$(3, 1)$\n\n$(2, 4)$\n\n↓\n\n↓\n\n$()$\n\n$(3, 1, 2, 4)$"},{"iden":"sample input 2","content":"2\n1 2"},{"iden":"sample output 2","content":"1 2"},{"iden":"sample input 3","content":"8\n4 6 3 2 8 5 7 1"},{"iden":"sample output 3","content":"3 1 2 7 4 6 8 5\n\nThe solution above is obtained as follows:\n\n$p$\n\n$q$\n\n$(4, 6, 3, 2, 8, 5, 7, 1)$\n\n$()$\n\n↓\n\n↓\n\n$(4, 6, 3, 2, 7, 1)$\n\n$(8, 5)$\n\n↓\n\n↓\n\n$(3, 2, 7, 1)$\n\n$(4, 6, 8, 5)$\n\n↓\n\n↓\n\n$(3, 1)$\n\n$(2, 7, 4, 6, 8, 5)$\n\n↓\n\n↓\n\n$()$\n\n$(3, 1, 2, 7, 4, 6, 8, 5)$"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}