Let C be the infimum of all reals α for which the following statement holds: for all positive integers m and nonnegative reals u1,…,um and v1,…,vm with ui+vi≤1, there exist z1,…,zm such that for every k, we have zk∈{vk,−uk}, and
i=1∑kzi−i=k+1∑mzi≤α.
Obtain upper and lower bounds on C that are as strong as possible.