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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::*;

fn read_line() -> String {
    let mut input = String::new();
    stdin().read_line(&mut input).unwrap();
    input.trim().to_string()
}

fn main() {
    let s = read_line();
    let mut count = 0;

    for c in s.chars() {
        if c == 'o' {
            count += 1;
            if count >= 8 {
                break;
            }
        }
    }

    match count + 15 - s.len() >= 8 {
        true => println!("YES"),
        false => println!("NO"),
    };
}