Из каждых трех стоящих рядом элементов определить минимальный элемент и переписать его в массив В

Dim a(1 To 18), b(1 To 18) As Integer
Randomize
List1.Clear
For i = 1 To 18
 a(i) = Int(Rnd(1) * 100 - 50)
 List1.AddItem a(i)
Next i
List1.AddItem " "
For i = 1 To 16
 If a(i) < a(i + 1) And a(i) < a(i + 2) Then b(i) = a(i)
 If a(i + 1) < a(i) And a(i + 1) < a(i + 2) Then b(i) = a(i + 1)
 If a(i + 2) < a(i + 1) And a(i + 2) < a(i) Then b(i) = a(i + 2)
 List1.AddItem b(i)
Next i

Function f(ByVal x As Integer) As Boolean
 For k = 2 To Sqr(Sqr(x ^ 2))
  If Int(x / k) = x / k Then f = True:  Exit For
 Next k
End Function
Private Sub Command14_Click()
List1.Clear
Dim a(), b() As Integer
Dim c, m, n As Integer
Dim e As String
 m = Val(Text1.Text): n = Val(Text2.Text)
 ReDim a(1 To m, 1 To n), b(1 To n)
Randomize
List1.AddItem "Исходная матрица"
For i = 1 To m
For j = 1 To n
 a(i, j) = Int(Rnd(1) * 100 - 50)
 e = e & Str(a(i, j)) & "  "
Next j
List1.AddItem e: e = ""
Next i
d = False
For i = 1 To m
For j = 1 To n
 d = f(a(i, j))
 If d = False Then b(j) = b(j) + a(i, j)
 If d = True Then b(j) = b(j) - a(i, j)
 d = False
Next j
Next i
List1.AddItem "Выходящий вектор"
For i = 1 To n
 e = e & Str(b(i)) & "  "
Next i
List1.AddItem e
End Sub