{"raw_statement":[{"iden":"problem statement","content":"We have $N$ bricks arranged in a row from left to right.\nThe $i$\\-th brick from the left $(1 \\leq i \\leq N)$ has an integer $a_i$ written on it.\nAmong them, you can break at most $N-1$ bricks of your choice.\nLet us say there are $K$ bricks remaining. Snuke will be satisfied if, for each integer $i$ $(1 \\leq i \\leq K)$, the $i$\\-th of those brick from the left has the integer $i$ written on it.\nFind the minimum number of bricks you need to break to satisfy Snuke's desire. If his desire is unsatisfiable, print `-1` instead."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $1 \\leq N \\leq 200000$\n*   $1 \\leq a_i \\leq N$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$a_1$ $a_2$ $...$ $a_N$"},{"iden":"sample input 1","content":"3\n2 1 2"},{"iden":"sample output 1","content":"1\n\nIf we break the leftmost brick, the remaining bricks have integers $1$ and $2$ written on them from left to right, in which case Snuke will be satisfied."},{"iden":"sample input 2","content":"3\n2 2 2"},{"iden":"sample output 2","content":"\\-1\n\nIn this case, there is no way to break some of the bricks to satisfy Snuke's desire."},{"iden":"sample input 3","content":"10\n3 1 4 1 5 9 2 6 5 3"},{"iden":"sample output 3","content":"7"},{"iden":"sample input 4","content":"1\n1"},{"iden":"sample output 4","content":"0\n\nThere may be no need to break the bricks at all."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}