using System;

namespace ConsoleApplication

{

    class Program

    {

 int [] X=new int[20];

 int i, n;

 private void dataGridView1_MouseClick(object sender, MouseEventArgs e)

 {

 n = int.Parse(textBox1.Text);

 dataGridView1.RowCount = n;

 dataGridView1.ColumnCount = 1;

 }

 private void button1_Click(object sender, EventArgs e)

 {

 n = int.Parse(textBox1.Text);

 for (i = 0; i < n; i++)

 X[i] = Convert.ToInt32(dataGridView1[0, i].Value);

 int br = 0;

 double S = 0, SR;

 for (i = 0; i < n && X[i] != 0; i++)

 if(X[i] % 2 == 0)

 {

 S += X[i];

 br++;

 }

 SR = S / br;

 label2.Text = "SR= " + SR.ToString("0.00");

 }

}

}