private void Box71_TextChanged(object sender, EventArgs e)
{
int[,] arr = mapTableToArray(); CCC = new CheckCorrectCell(arr);
if (CCC.checkCorrectCell9x9(7, 7) &&
Box71.Text != "")
{
Box71.BackColor = Color.Red;
}
else
Box71.BackColor = Color.White;
congratulations9x9();
}