package no164;

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		BigInteger min = null;
		for(int i=0;i<n;i++) {
			String s = sc.next();
			for(int radix=2;radix<=36;radix++) {
				try {
					BigInteger val = new BigInteger(s, radix);
					if (min == null) {
						min = val;
					}else{
						min = min.min(val);
					}
				} catch (Exception e) {
				}

			}
		}
		System.out.println(min);
	}

}