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 <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cassert>
#include <string>
#include <algorithm>
#include <vector>
#include <valarray>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <iomanip>
#include <map>
#include <set>
#include <list>
#include <limits>
#include <numeric>
#include <utility>
#include <deque>
#include <unordered_set>
#include <unordered_map>
#include <regex>
#include <array>
#include <bitset>
#include <complex>
#include <string>
#include <tuple>

using namespace std;
using ll = long long;
const int INF = 1e9;
const ll MOD = 1e9 + 7;

int main()
{
  string s;
  cin >> s;
  int cnt = 0;
  for (int i = 0; i < s.size(); ++i)
    if (s[i] == 'o')
      cnt++;
  if (15 - s.size() >= 8 - cnt)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;

  return 0;
}