import java.util.*;

class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);

		while (sc.hasNext()){
			String s1 = sc.nextLine();
			String s2 = sc.nextLine();
			int[] c1 = new int[123];
			int[] c2 = new int[123];

			//統計兩字串各字母出現個數
			for (int i = 0; i < s1.length(); i++)
				c1[s1.charAt(i)]++;
			for (int j = 0; j < s2.length(); j++)
				c2[s2.charAt(j)]++;

			//輸出較少數量那方的個數
			for (int k = 97; k <= 122; k++)
				for(int num = 0; num < Math.min(c1[k], c2[k]); num++)
					System.out.print((char)k);

			System.out.println();
		}
	}
}