Score : $100$ points
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.
321
0321
$321$ has three digits, so we need to add one leading zero to it to make it have four digits.
7777
7777
1
0001