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Time Limit: 2 s Memory Limit: 512 MB Total points: 100 Interactive

#1834. 歐拉圖?

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呢題係互動題。

我哋收埋咗一張有 $n$ 個頂點嘅無向圖 $G$。保證張圖連通,而且冇重邊同自環。

你最多可以問 60 次以下形式嘅問題:

  • 考慮 $G$ 嘅頂點集合嘅一個子集 $S$。由 $S$ 導出嘅子圖有幾多條邊?即係話,$G$ 入面有幾多條邊嘅兩個端點都喺 $S$ 入面?

你嘅目標係判斷張圖有冇歐拉迴路。歐拉迴路係一條恰好經過圖中每條邊一次,而且起點同終點相同嘅路徑。

留意,圖 $G$ 喺互動開始之前就已經固定。即係話,互動程式唔會因應查詢改變張圖。

輸入格式

第一行有一個整數 $n$($3 \le n \le 10^4$),代表 $G$ 嘅頂點數。保證 $G$ 最多有 $10^5$ 條邊,連通,而且冇重邊同自環。

互動

互動開始時,你要先讀入含有整數 $n$ 嘅一行。

要查詢 $G$ 入面由 $k$ 個頂點 $x_1,x_2,\ldots,x_k$ 導出嘅子圖有幾多條邊,就輸出一行,格式係 ? k x1 x2 ... xk($0 \le k \le n$,$1 \le x_i \le n$,所有 $x_i$ 都唔同)。

評測程式會回覆一行,入面有一個整數 $m$,即係呢啲邊嘅數量。

如果查詢唔合法,或者你問咗超過 60 次,評測程式會輸出 $-1$,然後結束互動。你會得到「答案錯誤」結果。請即刻終止程式,避免得到其他評測結果。

當你判斷到張圖有冇歐拉迴路,就輸出一行:有就輸出 ! YES,冇就輸出 ! NO。

每次輸出一行之後,記得輸出換行符號同清空輸出緩衝區。否則,你會得到「超出閒置時間限制」結果。

樣例

輸入格式 1

3
1
0

輸出格式 1

? 2 1 2
? 2 1 3
! NO

說明

樣例收埋嘅圖有 $3$ 個頂點,邊係 $(2,1)$ 同 $(2,3)$。

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