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 (Clang 3.8.0) (judge verdict: Accepted)

#include<stdio.h>

int main(void)
{
	int k = 0;
	char m[20];
	scanf("%s", m);
	int i;
	int n = 0;
	for (i = 0; i < 15; i++) {
		if ('o' == m[i] || 'x' == m[i]) {
			k++;
		}


	}
	for (i = 0; i < k; i++) {
		if ('o' == m[i]) {
			n++;
		}


	}
	if (n >= 8) {
		printf("YES");
	}
	else if (8 - n <= 15 - k) {
		printf("YES");
	}
	else {
		printf("NO");
	}
	return 0;
}