import std.algorithm;
import std.array;
import std.conv;
import std.math;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

void scan(T...)(ref T a) {
    string[] ss = readln.split;
    foreach (i, t; T) a[i] = ss[i].to!t;
}
T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;

void main() {
    string s = read!string;
    int n = 0;
    foreach (c; s) {
        if (c == 'o') n++;
    }

    auto m = 15 - s.length;
    if (n + m >= 8) writeln("YES");
    else writeln("NO");
}
