Given two strings of lowercase letters, a and b, print the longest string x of lowercase letters such that there is a permutation of x that is a subsequence of a and there is a permutation of x that is a subsequence of b. Input Input file contains several lines of input. Consecutive two lines make a set of input. That means in the inputfileline1and2isasetofinput,line3and4isasetofinputandsoon. Thefirstlineofapair 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 set of input, output a line containing x. If several x satisfy the criteria above, choose the first one in alphabetical order. Sample Input pretty women walking down the street Sample Output e nw et