import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        long ans = Long.MAX_VALUE;
        while (n-- > 0) {
            ArrayDeque<Integer> stack = new ArrayDeque<>();
            int max = 0;
            for (char c : sc.next().toCharArray()) {
                int v;
                if (c >= '0' && c <= '9') {
                    v = c - '0';
                } else {
                    v = c - 'A' + 10;
                }
                max = Math.max(max, v);
                stack.push(v);
            }
            long tmp = 0;
            long base = 1;
            while (stack.size() > 0) {
                tmp += base * stack.pop();
                base *= max + 1;
            }
            ans = Math.min(ans, tmp);
        }
        System.out.println(ans);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}