InvertRedBlue

def invertRedBlue(pict,k):
#@param:
#   pict: picture;
#   k: int;
    height = getHeight(pict)
    width = getWidth(pict)
    for x in range(0,width):
        if x<k:
            for y in range(0,height):
                pix = getPixel(pict,x,y)
                r = getRed(pix)
                b = getBlue(pix)
                setRed(pix,b)
                setBlue(pix,r)
    return(pict)