Xenia the beginner mathematician is a third year student at elementary school. She is now learning the addition operation.

The teacher has written down the sum of multiple numbers. Pupils should calculate the sum. To make the calculation easier, the sum only contains numbers 1, 2 and 3. Still, that isn't enough for Xenia. She is only beginning to count, so she can calculate a sum only if the summands follow in non-decreasing order. For example, she can't calculate sum 1+3+2+1 but she can calculate sums 1+1+2 and 3+3.

You've got the sum that was written on the board. Rearrange the summans and print the sum in such a way that Xenia can calculate the sum.

Input

The first line contains a non-empty string s — the sum Xenia needs to count. String s contains no spaces. It only contains digits and characters "+". Besides, string s is a correct sum of numbers 1, 2 and 3. String s is at most 100 characters long.

Output

Print the new sum that Xenia can count.

Examples

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初級(jí)數(shù)學(xué)家 Xenia 是小學(xué)三年級(jí)的學(xué)生。 她現(xiàn)在正在學(xué)習(xí)加法運(yùn)算。

老師寫(xiě)下了多個(gè)數(shù)字的和。 學(xué)生應(yīng)計(jì)算總和。 為了使計(jì)算更容易，總和只包含數(shù)字 1、2 和 3。但這對(duì) Xenia 來(lái)說(shuō)還不夠。 她才剛剛開(kāi)始數(shù)數(shù)，因此只有當(dāng)被加數(shù)按非遞減順序排列時(shí)，她才能計(jì)算總和。 例如，她無(wú)法計(jì)算 1+3+2+1 之和，但可以計(jì)算 1+1+2 和 3+3 之和。

你已經(jīng)得到了黑板上寫(xiě)的總數(shù)。 重新排列 summan 并以 Xenia 可以計(jì)算總和的方式打印總和。

輸入

第一行包含一個(gè)非空字符串 s — Xenia 需要計(jì)算的總和。 字符串 s 不包含空格。 它僅包含數(shù)字和字符“+”。 此外，字符串s是數(shù)字1、2和3的正確和。字符串s的長(zhǎng)度最多為100個(gè)字符。

輸出

打印 Xenia 可以計(jì)算的新總和。

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這次還是卡在split函數(shù)這里的。。。本次是需要轉(zhuǎn)義字符；