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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>

using namespace std;

static const char maru = 'o';
static const char batu = 'x';

int main(){
  string s;
  cin >> s;
  cin.ignore();

  int sum = 0;

  for (int i = 0; i < s.length(); i++){
    if(s[i] == maru){
      sum++;
    }
  }

  // 残り何日？

  if(8 - sum <= 0){
    cout << "YES" << endl;
    return 0;
  }

  int left = 15 - s.length();

  // 残り勝ち数

  int win = 8 - sum;

  if(win <= left){
    cout << "YES" << endl;
    return 0;
  }
  cout << "NO" << endl;
  return 0;
}