@amAturCodr, try this code and make sure to modify condition based on your requirement.
protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
TableCell cell = e.Row.Cells[1];
// int ID= int.Parse(cell.Text);//for numbers we use this method to extract first digit
string ID= cell.Text;
string firstdigit= ID.ToString().Substring(0,1);
if (firstdigit== "a")
{
cell.BackColor = Color.Red;
}
else if (firstdigit== "A")
{
cell.BackColor = Color.Yellow;
}
}
}