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<?php $act = new DateTime('2016-04-01 23:00:00'); $prev = null; $finish = new DateTime('2016-03-27 01:00:00'); while ($act > $finish) { $prev = clone $act; $act->sub(new DateInterval('PT1H')); $passed = assert($prev != $act); if (!$passed) { break; } } var_dump( $act );

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