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问题描述：

给定一个0到9999之间的整数，请以四个字符的形式打印该数字，如果数字不足四位数，则在前面补0.

例如，输入：548

则输出 0548

又如，输入3786

则输出 3786

Problem Statement

You are given an integer

N

between

0

and

9999

(inclusive).
Print it as a four-digit string after appending to it the necessary number of leading zeros.

Input is given from Standard Input in the following format:

$N$

Print the answer.