def f(t,a=range(44)):
 for e in s[0]:
	b=a[0]+1,
	for f,g,h in zip(t,a,a[1:]):b+=min(h,b[-1],g-(e==f))+1,;a=b
 return b[-1]
s=list(open('../fd/0'))
print''.join(sorted(s,key=f))