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import java.util.Scanner;
public class Main {
    
    public static void main(String[] args) {
        String str1 = "";
        String str2 = "";
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            str1 = in.nextLine();
            str2 = in.nextLine();
            post_order(str1,str2);
        }
    }
    
    static void post_order(String str1, String str2) {
        if (str1 == null || str1.equals("")) {
            return;
        }
        if(str1.length() == 1 && str1.equals(str2)) {
            System.out.print(str1);
        } else {
            String root = str1.substring(0,1);
            int index = str2.indexOf(root);
            post_order(str1.substring(1,index+1), str2.substring(0,index));
            post_order(str1.substring(index+1), str2.substring(index+1));
            System.out.print(root);
        }
    }
}
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