Find correct dates

Cost: $16|$ Solved: $8$

Memory limit: $256$ Mb

Time limit: $1000$ ms

Input file: stdin

Output file: stdout

$**$ Use only C$++**$

Task:

You are given a set of strings separated with line feed characters.

You need to find all the substrings that represent correct date formats. The correct date formats are: DD$.$MM$.$YY$,$ DD$.$MM$.$YYYY$,$ MM$.$DD$.$YY$,$ MM$.$DD$.$YYYY$,$ where DD$/$MM$/$YY are

day$/$month$/$two$-$digit format year respectively, YYYY is four$-$digit format year.

Surely, you know that the number of days can not exceed $29$ in February and $31$ in all other months.

Input:

A set of strings separated with line feed characters.

Output:

Output all the longest correct substrings in the order in which they appear in the text, separating each with a line feed character.

$**$ Use only C$++**$