static string gridChallenge(List grid) { for (int i = 0; i < grid.Count; i++) { char[] caracteres = grid[i].ToCharArray();

    for (int j = 0; j < caracteres.Length - 1; j++)
    {
        for (int k = 0; k < caracteres.Length - 1 - j; k++)
        {
            if (caracteres[k] > caracteres[k + 1])
            {
                char temp = caracteres[k];
                caracteres[k] = caracteres[k + 1];
                caracteres[k + 1] = temp;
            }
        }
    }

    grid[i] = new string(caracteres);
}

for (int i = 0; i < grid.Count - 1; i++)
{
    for (int j = 0; j < grid[i].Length; j++)
    {
        if (grid[i][j] > grid[i + 1][j])
        {
            return "NO";
        }
    }
}

return "YES";

}