import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		long min = Long.MAX_VALUE;
		int[] shinsu = new int[91];
		for (int i = 0; i < shinsu.length; i++) {
			if (i <= 57) {
				shinsu[i] = i - 47;
			} else {
				shinsu[i] = i - 54;
			}
		}

		for (int n = 0; n < N; n++) {
			int max = 0;
			char[] input = sc.next().toCharArray();
			/*
			 * char の 0~9はintの48~57 A~Zは65~90
			 */
			for (int i = 0; i < input.length; i++) {
				max = Math.max(max, (int) input[i]);
			}
			int shinho = shinsu[max];
			long ans = 0;
			long now = 1;
			for (int i = 0; i < input.length; i++) {
				char c = input[input.length - 1 - i];
				int conv = convert(c);
				ans += conv * now;
				now *= shinho;
			}
			min = Math.min(min, ans);
		}
		System.out.println(min);
	}

	static int convert(char c) {
		int n = (int) c;
		if (n <= 57) {
			n -= 48;
		} else {
			n -= 55;
		}
		return n;
	}

}