C# :: Matrix Of Buttons Variables?

There is a genereted matrix of buttons:

private void Single_Load(object sender, EventArgs e) {
//code here
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
//a lot of working code here
b[i, j].Click += new System.EventHandler(ClickButton);
}
}
}

What can I do when one of those buttons is pressed (i have the method ClickButton) to know what i and j has he?

I want to make something like this

ClickButton() {
if (x%2==0)
v[i, j] = x; //i and j should be form the matrix of buttons
}