program prob2
    implicit none
    integer::x1, x2, x3, x4, y1, y2, y3, y4, dx, dy
    read(*,*) x1, y1, x2, y2
    dx = x2 - x1
    dy = y2 - y1
    if(dx >= 0 .and. dy >= 0) then !-+
        x3 = x2 - dy
        y3 = y2 + dx
    else if(dx >= 0 .and. dy <= 0) then !++
        x3 = x2 - dy
        y3 = y2 + dx
    else if(dx <= 0 .and. dy >= 0) then !--
        x3 = x2 - dy
        y3 = y2 + dx
    else if(dx <= 0 .and. dy <= 0) then !+-
        x3 = x2 - y2
        y3 = y2 + x2
    end if
    x4 = x3 - dx
    y4 = y3 - dy
    write(*,*) x3, y3, x4, y4
    stop
end program