private void Box51_TextChanged(object sender, EventArgs e)
{
int[,] arr = mapTableToArray(); CCC = new CheckCorrectCell(arr);
if (CCC.checkCorrectCell9x9(5, 5) &&
Box51.Text != "")
{
Box51.BackColor = Color.Red;
}
else
Box51.BackColor = Color.White;
congratulations9x9();
}