RIOPLATENSE 2011 Problem 5

A form is the union of squared rectangles whose bases are consecutive unitary segments in a horizontal line that leaves all the rectangles on the same side, and whose heights $m_1, ... , m_n$ satisying $m_1\ge ... \ge m_n$ . An angle in a form consists of a box $v$ and of all the boxes to the right of $v$ and all the boxes above $v$ . The size of a form of an angle is the number of boxes it contains. Find the maximum number of angles of size $11$ in a form of size $400$ .

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