# The Bank Cards

# The Bank Cards

The bank "Kislovodsk" decided to introduce a new kind of bank cards. To do it, the identical blank cards were produced, that contains the special place for customer identification. Initially the code number **X** is written here. The bank has a special device that allows to erase some digits of **X**. The remaining numbers being recorded in a row, form a customer's account number. For example, if **X = 12013456789**, the account numbers **5**, **12**, **17** or **12013456789** can be obtained, but the numbers **22** or **71** impossible to obtain.

The distribution of account numbers in a bank is very simple. The accounts are assigned sequentially the numbers **1**, **2**, … Obviously, at some moment of the time there will appear the account number **N **that cannot be obtained from the digits of **X** with a way described above. The bank management wants to know the value of **N**.

Write a program that finds the value of **N** if **X** is given.

**Input**

The positive integer **X** (**1** ≤ **X** < **10 ^{1000}**) without leading zeroes.

**Output**

Print number **N** without leading zeroes.

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