func main()
	var a: []char :: cui@inputStr()
	var b: []char :: cui@inputStr()
	if(^a < ^b)
		do cui@print("\{b}\n")
	elif(^a > ^b)
		do cui@print("\{a}\n")
	else
		for i(0, ^a - 1)
			if(a[i] = b[i])
				skip i
			end if
			if(a[i] = '4' & b[i] = '7')
				do cui@print("\{a}\n")
			elif(a[i] = '7' & b[i] = '4')
				do cui@print("\{b}\n")
			elif(a[i] < b[i])
				do cui@print("\{b}\n")
			else
				do cui@print("\{a}\n")
			end if
			ret
		end for
	end if
end func