Um_nik was right!

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This was the first realization after not being able to solve a manageable problem in an important contest... I see editorial often which was the cause of this failure.

Um_nik said : ~~~~~ To do X you have to do X ~~~~~

You Should not see the editorial at al.

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So To solve problem in contest time(where i can't see the editorial) I have to solve problem without editorial. I used to hate Um_nik for his rude tone of writing but it turned out he was right...