Contest Duration: ~ (local time) (120 minutes)
B - Sumo /

Time Limit: 2 sec / Memory Limit: 1024 MB

### 問題文

k 日目までの取組が終了しました。 高橋君の取組の結果が o, x からなる長さ k の文字列 S で与えられます。 Si 文字目が o ならば高橋君が i 日目の取組で勝ったことを、 x ならば負けたことをそれぞれ表します。

### 制約

• 1 \leq k \leq 15
• So, x からなる長さ k の文字列である

### 入力

S


### 入力例 1

oxoxoxoxoxoxox


### 出力例 1

YES


### 入力例 2

xxxxxxxx


### 出力例 2

NO


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