import std.stdio;
import std.algorithm;
import std.math;
import std.conv;
import std.string;

T readNum(T)(){
  return readStr.to!T;
}

T[] readNums(T)(){
  return readStr.split.to!(T[]);
}

string readStr(){
  return readln.chomp;
}

void main(){
  string s = readStr;
  int l = s.length.to!int;

  if(s.count("o") + 15 - l >= 8){
    writeln("YES");
  } else {
    writeln("NO");
  }
}
