5676：ztr loves lucky numbers

ztr loves lucky numbers. Everybody knows that positive integers are lucky if their decimal representation doesn't contain digits other than 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

Lucky number is super lucky if it's decimal representation contains equal amount of digits 4 and 7. For example, numbers 47, 7744, 474477 are super lucky and 4, 744, 467 are not.

One day ztr came across a positive integer n. Help him to find the least super lucky number which is not less than n.

There are T$(1\leq\;n\leq\;10^{5})$ cases

For each cases:

The only line contains a positive integer $n(1\leq\;n\leq\;10^{18})$. This number doesn't have leading zeroes.

For each cases
Output the answer