<?php
	$n = trim(fgets(STDIN));
	$a = trim(fgets(STDIN));
	$a = explode(' ', $a);
	
	$now = count($a);
	$ans = 0;
	
	for($i = count($a) - 1; $i >= 0; $i--){
		if($a[$i] != $now){
			$ans++;
		}else{
			$now--;
		}
	}
	
	echo $ans."\n";
?>