Problems

# Common permutation

Given two strings of lowercase letters a and b. Print the longest string x that simultaneously is a substring of permutation of a and is a substring of permutation of b.

#### Input

Input consists of pairs of lines. The first line of a pair contains a and the second contains b. Each string is on a separate line and consists of at most 1000 lowercase letters.

#### Output

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.

Time limit 1 second
Memory limit 128 MiB
Input example #1
pretty
women
walking
down
the
street

Output example #1
e
nw
et