有如下VB程序段:
Dims As String, c As String, st As String
Dim n As Integer, i As Integer
s ="20zj20sx7":n=0:st=""
For i=1 To Len(s)
c=Mid(s,i,1)
If c>= "a" And c<= "z" Then
st=Chr(Asc("a") *2+25-Asc(c))+st
Else
n=n*10+ Val(c)
End If
Next i
st =st+str(n)
执行该程序段后,变量st的值是( )