The problem task in Russian isn't equal to the problem task in English. The English text have following sentence: "You have to put the fence in the minimum number of squares so that the goat will be able to visit exactly K squares." It means that our region built could contain only K squares and something else, for example halves squares (as in example). But in the problem task in Russian this sentence is as follows:
"Требуется, поставив минимальное число секций, предоставить козлу участок ровно из K квадратов."
It means that the region contains only K squares and nothing else.

I think that this sentence should be rewritten as follows:
"Требуется, поставив минимальное число секций, предоставить козлу возможность посетить ровно K квадратов."


And something else.

English sentence contains phrase: "to put the fence in the minimum number of squares". But how should we count number of squares if the fence is put on the bound of two squares?!!