{"raw_statement":[{"iden":"problem statement","content":"We have a permutation $p$ = {$p_1,\\ p_2,\\ ...,\\ p_n$} of {$1,\\ 2,\\ ...,\\ n$}.\nPrint the number of elements $p_i$ ($1 < i < n$) that satisfy the following condition:\n\n*   $p_i$ is the second smallest number among the three numbers $p_{i - 1}$, $p_i$, and $p_{i + 1}$."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $3 \\leq n \\leq 20$\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":"5\n1 3 5 4 2"},{"iden":"sample output 1","content":"2\n\n$p_2 = 3$ is the second smallest number among $p_1 = 1$, $p_2 = 3$, and $p_3 = 5$. Also, $p_4 = 4$ is the second smallest number among $p_3 = 5$, $p_4 = 4$, and $p_5 = 2$. These two elements satisfy the condition."},{"iden":"sample input 2","content":"9\n9 6 3 2 5 8 7 4 1"},{"iden":"sample output 2","content":"5"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}