Greg is a beginner bodybuilder. Today the gym coach gave him the training plan. All it had was n integers a1,?a2,?...,?an. These numbers mean that Greg needs to do exactly n exercises today. Besides, Greg should repeat the i-th in order exercise ai times.

Greg now only does three types of exercises: "chest" exercises, "biceps" exercises and "back" exercises. Besides, his training is cyclic, that is, the first exercise he does is a "chest" one, the second one is "biceps", the third one is "back", the fourth one is "chest", the fifth one is "biceps", and so on to the n-th exercise.

Now Greg wonders, which muscle will get the most exercise during his training. We know that the exercise Greg repeats the maximum number of times, trains the corresponding muscle the most. Help Greg, determine which muscle will get the most training.

Input

The first line contains integer n (1?≤?n?≤?20). The second line contains n integers a1,?a2,?...,?an (1?≤?ai?≤?25) — the number of times Greg repeats the exercises.

Output

Print word "chest" (without the quotes), if the chest gets the most exercise, "biceps" (without the quotes), if the biceps gets the most exercise and print "back" (without the quotes) if the back gets the most exercise.

It is guaranteed that the input is such that the answer to the problem is unambiguous.

Examples

input

2

2 8

output

biceps

input

3

5 1 10

output

back

input

7

3 3 2 7 9 6 8

output

chest

Note

In the first sample Greg does 2 chest, 8 biceps and zero back exercises, so the biceps gets the most exercises.

In the second sample Greg does 5 chest, 1 biceps and 10 back exercises, so the back gets the most exercises.

In the third sample Greg does 18 chest, 12 biceps and 8 back exercises, so the chest gets the most exercise.

中文：

格雷格是一名初學(xué)者健美運(yùn)動(dòng)員。 今天健身房教練給了他訓(xùn)練計(jì)劃。 它只有 n 個(gè)整數(shù) a1,?a2,?...,?an。 這些數(shù)字意味著 Greg 今天剛好需要做 n 次練習(xí)。 此外，Greg 應(yīng)該重復(fù)第 i 個(gè)，以便練習(xí) ai 次。

格雷格現(xiàn)在只做三種運(yùn)動(dòng)：“胸部”運(yùn)動(dòng)、“二頭肌”運(yùn)動(dòng)和“背部”運(yùn)動(dòng)。 而且，他的訓(xùn)練是循環(huán)的，即第一個(gè)動(dòng)作是“胸”，第二個(gè)是“二頭肌”，第三個(gè)是“背”，第四個(gè)是“胸”，第五個(gè)是“胸”。 “二頭肌”，以此類推到第n個(gè)練習(xí)。

現(xiàn)在格雷格想知道，在他的訓(xùn)練中，哪塊肌肉會(huì)得到最多的鍛煉。 我們知道格雷格這個(gè)動(dòng)作重復(fù)次數(shù)最多，對(duì)應(yīng)的肌肉訓(xùn)練最多。 幫助格雷格，確定哪塊肌肉將得到最多的訓(xùn)練。

輸入

第一行包含整數(shù) n (1 ≤ n ≤ 20)。 第二行包含 n 個(gè)整數(shù) a1,?a2,?...,?an (1?≤?ai?≤?25)——Greg 重復(fù)練習(xí)的次數(shù)。

輸出

如果胸部得到最多的鍛煉，則打印單詞“chest”（不帶引號(hào)）；如果二頭肌得到最多的鍛煉，則打印“biceps”（不帶引號(hào)）；如果背部得到鍛煉，則打印“back”（不帶引號(hào)）。 大多數(shù)鍛煉。

保證輸入的問題的答案是明確的。

只要依次去計(jì)算每種運(yùn)動(dòng)鍛煉了多少次即可。