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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <string.h>

int main(void){
  char S[15];
  int num[15];
  int n;
  int i,j=1, x=0;
  
  gets(S);
  n=strlen(S);
  
  for(i=0; i<n; i++){
    if(S[i]=='o'){
      x++;
    }
    num[i]=x;
  }
  
  
  for(i=7; i<n-1; i++){
    x=num[i];
    if(i-x<7){
      j=0;
    }else{
      j=1;
    }
  }
  
  
  if(j==0){
    printf("YES");
  }else{
    printf("NO");
  }
  
  return 0;
}