-- Try AtCoder
-- author: Leonardone @ NEETSDKASU

main = print . solve . map read . words =<< getLine

solve [a, b, c] = ans where
    f x y z = x * y * (z - div z 2) - x * y * (div z 2)
    ans = minimum [f a b c, f b c a, f c a b]