Android Question store 4 variables in persistent (flash memory)

kvs.Put("a", a)
kvs.Put("b", b)
kvs.Put("c", c)
kvs.Put("d", d)

kvs.get("a", a)
kvs.get("b", b)
kvs.get("c", c)
kvs.get("d", d)

Private Sub btnSave_Click   
    
    kvs.put("ramvar",flashvar)
    LBL_rate1.text = "saved"& titi
    
End Sub

Dim a As String ="Paris"
    Dim b As String ="London"
    Dim c As String ="Athens"
    Dim d As String ="Geneva"

    Dim m As Map
    m.Initialize
    m.Put("a", a)
    m.Put("b", b)
    m.Put("c", c)
    m.Put("d", d)
   
    'save map:
    File.WriteMap( xui.DefaultFolder, "mycities", m)
   
    'Read the map
    Dim mp As Map =File.ReadMap(xui.DefaultFolder, "mycities")
    Log(mp.Get("c"))   'returns the value for the key c which is: Athens

a = kvs.getdefault("a", someinitialvalue)

    kvs.Initialize(File.DirDefaultExternal, "variabl")