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某字符串加密算法，规则如下：
（1）根据字符串长度构建一个最小的n*n矩阵，将字符串中每个字符从左到右，自上而下顺序填入矩阵，不足部分用字符“*”代替；
（2）将矩阵转置（行列对换），然后将奇数行字母内码加上1，偶数行字母内码减1，字符为a、z或A、Z时做循环处理。比如，字符a减1为z；字符Z加1为A。
（3）按从左到右，从上而下依次取出字符，形成新的字符串。如图a为字符串“Go to the zoo.”的加密过程。编写VB程序，在文本框Text1中输入字符串，点击“加密”按钮，在文本框Text2中输出加密后的字符串。程序运行结果如图b所示。

图a

图b

（1）若在文本框Text1中输入3个字母“Far”，执行加密程序后，输出结果为___。
（2）实现上述功能的 VB 程序如下，请在划线处填入合适的代码
Dim a(1 To 100) As String, b(1 To 100) As String, n As Integer
Private Sub Command1_Click()
Dim s1 As String, s2 As String，i As Integer, j As Integer, m As Single
s1 = Text1.Text
m = Sqr(Len(s1))
If m > Int(m) Then n = Int(m) + 1 Else n = m
For i = 1 To n * n
If i <= Len(s1) Then  a(i) = Mid(s1, i, 1)   Else  a(i) = "*"
Next i
For i = 1 To n
For j = 1 To n
b((i - 1) * n + j) = ___________‘将矩阵转置
b((i - 1) * n + j) = jm(i,j)   ‘内码变换
Next j
Next i
s2 = ""
For i = 1 To n * n
s2 = s2 & b(i)
Next i
Text2.Text = s2
End Sub
Function jm(x As Integer, y As Integer) As String
Dim s As String
s = b((x - 1) * n + y)
If s <= "Z" And s >= "A" Or s <= "z" And s >= "a" Then
If x Mod 2 <> 0 Then
If s <> "Z" And s <> "z" Then
s = Chr(Asc(s) + 1)
Else
s = Chr(Asc(s) - 25)
End If
Else
If s <> "a" And s <> "A" Then
s = Chr(Asc(s) - 1)
Else
s = __________
End If
End If
End If
_________
End Function