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In front of you there is a screen divided into k vertical strips that are marked by the numbers 1, 2, ..., k from left to right. In the bottom of the screen there is an aircraft that can fly through the strips (from one strip only to the next strip). It needs 1 second to move to the next strip of the screen. N diamonds are falling from the upper part of the screen. There is a known price [] for every diamond, a strip l into which it falls (a certain diamond falls into this exact strip) and the known moment t when it touches the bottom of the screen. The aircraft is as wide as a strip and can take the diamond only when it has its entire width in the strip where the diamond is falling and when it is there at the exact moment when the diamond touches the bottom of the screen. If the aircraft begins to cross to another strip at the moment x, it will then find itself with its entire width in the neighboring strip at the moment x+1. So, if the aircraft begins to cross at the moment x into the neighboring strip s1 (s1 is s-1 or s+1), then it will pick up the diamonds in the strip s that are there at the moment x and the s1 diamonds that at the moment x+1 touch the bottom of the screen. While the entire width of the aircraft is in one strip, it can remain there indefinitely.