Given two strings of lowercase letters $a$ and $b$. Print the longest string $x$ that is simultaneously a substring of the permutation of $a$ and a substring of the permutation of $b$. \InputFile Consists of multiple test cases, each contains a pair of lines. The first line of a pair contains $a$ and the second line contains $b$. Each string is on a separate line and consists of at most $1000$ lowercase letters. \OutputFile For each subsequent pair of input lines print a line containing $x$. If several $x$ satisfy the criteria above, choose the first one in alphabetical order.