[code=plaintext]

Public Class Form3
    Dim a() As String
    Dim n, s, b As Integer
    Dim k As Integer

    Private Sub Textbox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

        If Not Char.IsDigit(e.KeyChar) Then
            e.Handled = True
            MsgBox("только ввод цифр")
        End If

    End Sub
    Private Sub Textbox3_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox3.KeyPress

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As system.EventArgs) Handles Button1.Click
        n = TextBox1.Text
        For i As Integer = 1 To n
            a(i) = Rnd() * 85 + 12
        Next
        b = a(1)
        k = 0
        For i As Integer = 0 To n
            b = a(i)
            If b < 0 And b + 1 > 0 Then
                If Math.Abs(b) = Math.Abs(b + 1) Then
                    k += 1
                End If
            End If

        Next
        TextBox3.Text = k
    End Sub
End Class