Xuanxuan has $n$ sticks of different length. One day, she puts all her sticks in a line, represented by $s_1, s_2, s_3, ..., s_n$. After measuring the length of each stick $s_k~(1 \le k \le n)$, she finds that for some sticks $s_i$ and $s_j~(1 \le i < j \le n)$, each stick placed between $s_i$ and $s_j$ is longer than $s_i$ but shorter than $s_j$. Now given the length of $s_1, s_2, s_3, ..., s_n$, you are required to find the maximum value $j~–~i$. \InputFile Contains multiple test cases. Each case contains two lines. First line is a single integer $n~(n \le 50000)$, indicating the number of sticks. Second line contains $n$ different positive integers (not larger than $10^5$), indicating the length of each stick in order. \OutputFile Output the maximum value $j~–~i$ in a single line. If there is no such $i$ and $j$, just output $-1$. \includegraphics{https://static.eolymp.com/content/1u/1ubiuinukt5ahe5mnq26fr40mc.gif}