private void button1_Click(object sender, EventArgs e)
        {
            dataGridView2.Visible = true;
            List
 _product = new List();            int Count = 1;
            foreach (DataGridViewRow row in dataGridView1APen.Rows)
            {
                if (row.Cells[0].Value != "" && row.Cells[0].Value != null)
                {
                    if (_product.Where(x => x.SoinikNo.ToLower() == row.Cells[0].Value.ToString().ToLower()).Any())
                    {
                        string Utsob = (Convert.ToInt32(_product.Where(x => x.SoinikNo.ToLower() == row.Cells[0].Value.ToString().ToLower()).Select(x => x.Utsob).FirstOrDefault()) + Convert.ToInt32(row.Cells[13].Value.ToString())).ToString();
                        string Pension = (Convert.ToInt32(_product.Where(x => x.SoinikNo.ToLower() == row.Cells[0].Value.ToString().ToLower()).Select(x => x.Pension).FirstOrDefault()) + Convert.ToInt32(row.Cells[12].Value.ToString())).ToString();
                        _product.Where(x => x.SoinikNo.ToLower() == row.Cells[0].Value.ToString().ToLower()).ToList().ForEach(x => { x.Utsob = Utsob; x.Pension = Pension; });
                    }
                    else
                    {
                        _product.Add(new ProductList
                        {
                            Sno = Count,
                            SoinikNo = row.Cells[2].Value.ToString(),
                            APenName = row.Cells[3].Value.ToString(),
                            Pension = row.Cells[12].Value.ToString(),
                            Utsob = row.Cells[13].Value.ToString()
                        });
                        Count++;
                    }
                }
            }
            dataGridView2.DataSource = _product;
        }
    }
}