In this paper, we consider the LOCC distinguishability of product states. We employ polygons to analyse orthogonal product states in any system to show that with LOCC protocols, to distinguish 7 orthogonal product states, one can exclude 4 states via a single copy. In bipartite systems, this result implies that N orthogonal product states are LOCC distinguishable if $left lceil frac {N}{4}right rceil$ copies are allowed, where $left lceil lright rceil$ for a real number $l$ means the smallest integer not less than $l$. In multipartite systems, this result implies that N orthogonal product states are LOCC distinguishable if $left lceil frac {N}{4}right rceil +1$ copies are allowed. We also give a theorem to show how many states can be excluded via a single copy if we are distinguishing n orthogonal product states by LOCC protocols in a bipartite system. Not like previous results, our result is a general result for any set of orthogonal product states in any system.
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