excel - How to use same cell formula value as input for the same formula? -

i need solve this:

on excel cell a3 use custom vba formula =smoothticker(a1,a2) function must use it's a3 cell output input value

function smoothticker(ticker integer, increment integer)     if (ticker > smoothticker , ticker - smoothticker > increment)         smoothticker = ticker     else         smoothticker = smoothticker     end if  end function 

in case can't use smoothticker variable input value please help! thank you

does want?

private smoothtickervalue integer  function smoothticker(ticker integer, increment integer)     if (ticker > smoothtickervalue , ticker - smoothtickervalue > increment)         smoothtickervalue = ticker     end if     smoothticker = smoothtickervalue  end function 

the problem doing kind of thing excel doesn't calculate contiguous cells in order , doesn't recalculate cells unless inputs change - kind of calculation may not work expected.