public static string isBalanced(string s)
{
    Stack<char> st = new();
    foreach (char chr in s.ToArray())
    {   
        if (new char[]{'(','[','{'}.Contains(chr)) st.Push(chr);
        else if ( st.Count > 0 && (int)chr > (int)st.Peek() && (int)chr-2 <= (int)st.Pop()) continue;
        else return "NO";  
    }   
    
    return (st.Count > 0)?"NO":"YES";
}