Sub test()
Dim LastRow&
Sheets(1).Cells.Clear
Sheets(1).Cells(1, 1).Resize(Int((Rnd * Hour(Time) * Minute(Time)) * Second(Time)) + 1) = "=ROW()*COLUMN()"
LastRow = Sheets(1).Cells(Application.Rows.Count, 1).End(xlUp).Row
MsgBox "Première ligne non vide en colonne A : " & LastRow & vbNewLine & _
"Nombre de lignes de la feuille : " & Format(Application.Rows.Count, "#,##0")
End Sub