Monocarp is playing a computer game. He's going to kill n monsters, the i-th of them has hi health.

Monocarp's character has two spells, either of which he can cast an arbitrary number of times (possibly, zero) and in an arbitrary order:

choose exactly two alive monsters and decrease their health by 1;

choose a single monster and kill it.

When a monster's health becomes 0, it dies.

What's the minimum number of spell casts Monocarp should perform in order to kill all monsters?

Monocarp 正在玩電腦游戲。 他要?dú)⑺?n 個(gè)怪物，其中第 i 個(gè)的生命值很高。

Monocarp 的角色有兩個(gè)法術(shù)，他可以以任意順序施展任意次數(shù)（可能為零）：

選擇恰好兩個(gè)活著的怪物并將其生命值降低 1；

選擇一個(gè)怪物并殺死它。

當(dāng)怪物的生命值變?yōu)?時(shí)，它就會(huì)死亡。

為了殺死所有怪物，Monocarp 最少需要施展多少次法術(shù)？

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對(duì)于生命值大于1的怪物，肯定是一招消滅掉最省時(shí)間了，只有是生命值為1的怪物才有一次選2個(gè)怪物，然后生命值－1的必要，于是就是求數(shù)組中1的怪物的數(shù)量即可；

當(dāng)然還要判斷一下奇數(shù)還是偶數(shù)；

下面是代碼：