func main()
	var n: int :: cui@inputInt()
	var ans: int :: lib@intMax
	for(1, n)
		var s: []char :: cui@input()
		do ans :: [ans, f(s)].min()
	end for
	do cui@print("\{ans}\n")
	
	func f(s: []char): int
		var d: int :: 0
		for i(0, ^s - 1)
			do d :: [d, g(s[i])].max()
		end for
		do d :+ 1
		var res: int :: 0
		for i(0, ^s - 1)
			do res :* d
			do res :+ g(s[i])
		end for
		ret res
		
		func g(c: char): int
			if(c <= '9')
				ret c $ int - '0' $ int
			else
				ret c $ int - 'A' $ int + 10
			end if
		end func
	end func
end func