function CalculateSum(form)
{
	var v1 = parseFloat(form.Text1.value);
	var v2 = parseFloat(form.Text2.value);
	var v3 = parseFloat(form.Text3.value);
	var v4 = parseFloat(form.Text4.value);
	var v5 = parseFloat(form.Text5.value);
	var v6 = parseFloat(form.Text6.value);
	var v7 = parseFloat(form.Text7.value);
	var v8 = parseFloat(form.Text8.value);
	var v9 = parseFloat(form.Text9.value);
	var v10 = parseFloat(form.Text10.value);
	var v11 = parseFloat(form.Text11.value);
	var v12 = parseFloat(form.Text12.value);
	var v13 = parseFloat(form.Text13.value);

	var t = v1 + v2 + v3 + v4 + v5 + v6 + v7 + v8 + v9 + v10 + v11 + v12 + v13

	var bNumber = isNaN(t);

	if (bNumber) {
		form.Text20.value = 0;
	}
	else {
		form.Text20.value = t;

	}
}