取一元、二元、五元的硬币共23枚（每种硬币至少取1枚），付给45元钱，有______种不同的取法。（仅回答有多少种）

Private Sub Command0_Click()
Dim n As Integer, m As Integer, p As Integer, q As Integer, s As Integer, a As Integer
s = 23
a = 45
q = 0
If s = n + m + p And a = n + 2 * m + 5 * p Then
q = q + 1
End If
MsgBox q
End Sub
为什么不可以哦?

dim a,b,c as integer,s,n as integer
if a>=1 and b>=1 and c>=1 then
if a+b+c=23 and 2*a+1*b+5*c=45 then
n=n+1
end if
end if
msgbox "a" & a & "b" & b & "c" & c & "total" & n