Message informing when the stock is egual or minimum

private void button1_Click(object sender, EventArgs e)
{
   Int32 number = 0; Boolean success = false;
   success = Int32.TryParse(textBox1.Text, number);
   if (!success)
    MessageBox.Show("Please enter a valid integer value!");
   else
   if (number >= 5)
   MessageBox.Show("Stock is minimum");
}