int main() {
	string t;
	while (cin >> t) {
		int i = 0, len = t.size(), cnt = 1, sign = 1;
		for (int i = 0; i < len; i++)
			if (t[i] != '#')
				t[i] = 'a';//只区分叶子和非叶子
		while (i < len) {
			if (i == 0)cnt = 1;
			string t1 = t.substr(i, cnt), t2 = t1;
			reverse(t1.begin(), t1.end());
			if (t1 != t2) {
				sign = 0; break;
			}
			i += cnt; cnt = 0;
			for (int i = 0; i < t1.size(); i++)
				if (t1[i] != '#')cnt++;
			cnt *= 2;
		}
		if (sign)cout << "YES" << endl;
		else cout << "NO" << endl;
	}
}