Problem:
Score : 200 points

Problem Statement

Takahashi is competing in a sumo tournament.
The tournament lasts for 15 days, during which he performs in one match per day.
If he wins 8 or more matches, he can also participate in the next tournament.

The matches for the first k days have finished.
You are given the results of Takahashi's matches as a string S consisting of o and x.
If the i-th character in S is o, it means that Takahashi won the match on the i-th day; if that character is x, it means that Takahashi lost the match on the i-th day.

Print YES if there is a possibility that Takahashi can participate in the next tournament, and print NO if there is no such possibility.

Constraints

1 \leq k \leq 15

S is a string of length k consisting of o and x.

Input

Input is given from Standard Input in the following format:

S

Output

Print YES if there is a possibility that Takahashi can participate in the next tournament, and print NO otherwise.

Sample Input 1

oxoxoxoxoxoxox

Sample Output 1

YES

Takahashi has 7 wins and 7 losses before the last match. If he wins that match, he will have 8 wins.

Sample Input 2

xxxxxxxx

Sample Output 2

NO

Solution in PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
fscanf(STDIN,"%s",$str);

$cnt_0=0;
$cnt_x=0;
$s=false;

for($i=0;$i<strlen($str);$i++){
	if(substr($str,$i,1)=="o"){
		$cnt_o++;
	}else{
		$cnt_x++;
	}
	
	if($cnt_o==7 && $i<15){
		echo "YES";
		break;
	}
	if($cnt_x==8){
		echo "NO";
		break;
	}
	
	if($cnt_o==8){
		echo "YES";
		break;
	}
}


?>