let f = function
    | 0 , 0 , 0 -> 0
    | 0 , 1 , 1 -> 0
    | 1 , 0 , 1 -> 0
    | 1 , 1 , 0 -> 0
    | _         -> 1

for a in 0..1 do
    for b in 0..1 do
        for c in 0..1 do
            printfn "%i xor %i xor %i = %i" a b c (f (a, b, c))