import java.util.*;
import java.lang.*;
import java.math.*;

public class Main {

    void run() {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();

        boolean flg = true;
        BigInteger ans = BigInteger.ZERO;

        for(int i = 0; i < N; i++) {
        	String v = sc.next();
        	for(int radix = 2; radix < 37; radix++) {
        		try {
        			BigInteger tmp = new BigInteger(v, radix);
        			if(flg == true || ans.compareTo(tmp) == 1) {
        				ans = tmp;
        				flg = false;
        			}
        		}
        		catch(Exception e) {
        			// do nothing
        		}
        	}
        }

        System.out.println(ans);
    }

    public static void main(String[] args) {
        new Main().run();
    }
}