import java.util.*;class n{static{String[]a=new String[99];Scanner c=new Scanner(System.in);int i=0;for(;c.hasNext();a[i++]=c.next());for(i=0;i<20;++i)for(String s:a)if(s!=null&&i<s.length())System.out.print(s.charAt(i));}}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).