import java.util.Scanner;


public class Main_yukicoder164 {

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

        int n = sc.nextInt();
        long min = Long.MAX_VALUE;
        for (int i = 0; i < n; i++) {
        	char[] num = sc.next().toCharArray();

        	int base = 0;
        	for (char c : num) {
        		if (c >= '0' && c <= '9') {
        			base = Math.max(base, c - '0');
        		} else {
        			base = Math.max(base, c - 'A' + 10);
        		}
        	}
        	base += 1;

        	long tmp = 0;
        	for (char c : num) {
        		tmp *= base;

        		if (c >= '0' && c <= '9') {
        			tmp += c - '0';
        		} else {
        			tmp += c - 'A' + 10;
        		}
        	}

        	min = Math.min(min, tmp);
        }

        System.out.println(min);

        sc.close();
    }
}