<?php /*atcoder.php*/

$at = new Atcoder();
$at->main();
unset($at);

class Atcoder{
	private function lineIn(){
		$buf = fgets(STDIN);
		return $this->killNewLine($buf);
	}
	private function killNewLine($buf = null){
		$buf = str_replace("\r\n", "", $buf);
		$buf = str_replace("\n", "", $buf);
		$buf = str_replace("\r", "", $buf);
		return $buf;
	}

	public function main(){
		$n = $this->lineIn();
		$s = $this->lineIn();	
	
		$ans = 0;

		$ans = substr_count($s, "#.");
		
		echo $ans . "\n";

	}
}
?>
