Переставить местами строку матрицы с max элементом и строку с минимальным средним арифметическим

.Sub matr()
Dim a() As Integer
Dim s() As Integer
Dim sr() As Integer
n = InputBox("введите размер массива")
ReDim a(n, n) As Integer
ReDim s(n) As Integer
ReDim sr(n) As Integer
For i = 1 To n
For j = 1 To n
a(i, j) = InputBox("Введите A(" & i & ", " & j & "):")
Next j, i
msgString = ""
For i = 1 To n
For j = 1 To n
msgString = msgString & a(i, j) & ", "
Next j
msgString = msgString & Chr(13)
Next i
MsgBox ("Массив А:" & Chr(13) & msgString)
Max = a(1, 1): nmax = 1
Min = a(1, 1): nmin = 1
k = 1
For i = 1 To n
For j = 1 To n
s(k) = s(i) + a(i, j)
Next j
k = k + 1
Next i
For i = 1 To k
sr(i) = s(i) / n
If sr(1) < sr(i) Then
nmin = i
End If
Next i
For i = 1 To n
For j = 1 To n
If a(i, j) > Max Then
Max = a(i, j)
nmax = i
End If
Next j
Next i
MsgBox ("Минимальный" & Str(Min) & Chr(13) & "Максимальный" & Str(Max))
For j = 1 To n
t = a(nmin, j)
a(nmin, j) = a(nmax, j)
a(nmax, j) = t
Next j
msgString = ""
For i = 1 To n
For j = 1 To n
msgString = msgString & a(i, j) & ", "
Next j
msgString = msgString & Chr(13)
Next i
MsgBox ("Массив А после обмена:" & Chr(13) & msgString)
End Sub

smin = s(1) / n
For i = 2 To k
    sr(i) = s(i) / n
    If smin > sr(i) Then
        smin = sr(i)
        nmin = i
    End If
Next i