#include<bits/stdc++.h>
using namespace std;
int n,ans=0;
string s;
int main(){
	cin>>s;
	n=s.length();
	for(int i=1;i<=s.length();i++){
		if(s[i-1]=='o') ans++;
	}
	if(n-ans<=7) cout<<"YES";
	else cout<<"NO";
}
