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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        HashMap<Character, Integer> map = new HashMap<>();
        for (int i = 0; i < 10; i++) {
            map.put((char)(i + '0'), i);
        }
        for (int i = 0; i < 26; i++) {
            map.put((char)(i + 'A'), i + 10);
        }
        long ans = Long.MAX_VALUE;
        while (n-- > 0) {
            char[] inputs = sc.next().toCharArray();
            int max = 0;
            for (char c : inputs) {
                max = Math.max(max, map.get(c));
            }
            int base = max + 1;
            long current = 0;
            for (char c : inputs) {
                current *= base;
                current += map.get(c);
            }
            ans = Math.min(ans, current);
        }
        System.out.println(ans);
    }
    
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    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 int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}