2
2 6 8 1 3 1
2 1 3 8 6 7
 2
1 8 9 1 1 0
2 3 4 5 6 7
 2
0 2 9 8 1 7
6 7 4 3 2 5
 3
9 4 6 2 7 0
3 7 1 9 6 4
6 1 0 8 7 2
 3
2 7 4 0 7 1
5 5 4 9 1 4
2 1 7 5 1 7
 3
5 1 2 9 6 4
9 0 6 4 2 8
4 6 2 8 3 7
 3
1 1 1 0 2 3
4 5 6 7 8 9
0 0 0 0 0 0
 1
1 9 8 3 7 8
 3
2 6 3 7 1 0
9 1 2 4 7 6
1 4 8 7 6 2
 1
4 6 9 8 2 7
 2
1 7 6 9 2 5
1 6 7 0 9 2
 3
4 1 0 8 0 2
1 5 3 5 0 7
7 7 2 7 2 2
 1
7 6 5 8 9 0
 3
3 8 3 5 5 5
3 0 1 6 6 3
0 4 3 7 2 4
 1
8 1 9 2 9 7
 2
2 0 5 7 0 8
4 5 1 5 4 9
 3
1 1 1 1 1 1
0 2 3 4 5 6
7 8 9 2 3 4
 3
0 1 1 2 2 3
4 5 6 7 8 9
3 4 5 6 7 1
 1
0 8 7 1 3 2
 2
9 3 3 6 7 2
6 2 9 1 5 9
 1
8 2 7 4 1 0
 2
3 6 8 9 5 0
6 7 0 8 2 3
 1
0 1 2 3 4 5
 3
3 4 5 6 8 9
1 1 1 1 1 1
1 2 4 5 7 0
 2
2 3 5 1 9 6
1 6 8 7 3 9
 2
0 9 5 7 6 2
8 6 2 7 1 4
 2
4 3 8 6 0 1
4 7 1 8 9 0
 1
6 2 8 4 5 1
 1
4 0 9 6 3 1
 2
6 0 1 7 2 9
1 3 4 6 7 0
 3
5 0 7 6 2 1
2 7 4 6 1 9
0 2 6 1 7 5
 3
0 1 1 2 2 3
4 5 6 7 8 9
3 4 5 6 7 8
 3
0 1 2 3 4 5
0 1 2 3 4 5
0 1 2 3 4 5
 2
2 4 0 3 7 6
3 2 8 7 1 5
 1
7 3 6 9 8 1
 3
1 1 2 3 4 5
6 7 8 9 0 2
3 4 5 6 7 8
 3
9 4 3 0 2 6
7 0 5 3 3 9
1 0 7 4 6 7
 1
3 7 7 6 4 2
 3
2 5 7 4 2 7
1 5 5 9 0 3
8 2 0 1 5 1
 2
1 7 8 6 0 9
3 2 1 7 4 9
 2
0 8 6 2 1 3
5 2 7 1 0 9
 2
5 3 2 9 8 2
0 7 4 8 1 8
 3
3 8 5 1 5 5
1 5 7 2 6 9
4 3 4 8 8 9
 2
5 1 2 3 0 8
3 6 7 4 9 2
 2
0 1 2 3 4 5
6 7 8 9 1 2
 1
5 3 8 0 2 6
 1
0 7 6 3 2 4
 2
8 0 6 5 1 4
7 1 0 8 3 4
 2
7 8 6 1 4 5
8 6 4 3 2 5
 2
0 1 2 3 4 5
6 6 6 7 8 9
 3
9 3 1 8 4 6
6 9 1 2 0 7
8 9 1 5 0 3
 3
0 6 2 9 5 4
3 8 0 1 6 9
6 9 0 1 5 2
 3
0 1 2 2 4 5
6 7 8 9 0 1
3 3 4 5 6 7
 1
1 4 5 7 0 5
 2
8 6 4 1 2 0
7 8 5 3 2 1
 3
5 6 2 9 3 5
5 4 1 5 9 8
4 4 2 0 3 5
 1
9 8 1 6 5 7
 3
7 2 1 3 6 9
0 3 8 4 7 6
1 4 5 8 7 0
 3
9 4 3 3 9 3
1 0 3 4 5 3
2 9 6 2 4 1
 3
1 2 3 7 8 9
9 8 7 1 2 3
7 9 2 3 1 8
 3
8 1 8 2 7 1
9 1 9 9 4 7
0 0 9 0 4 0
 1
2 5 9 6 7 9
 3
4 6 0 3 9 2
8 6 9 0 7 2
6 9 3 2 5 7
 3
8 6 0 5 4 9
1 8 5 3 9 7
7 4 5 1 6 8
 1
8 6 0 9 4 2
 1
7 9 2 5 0 4
 1
6 0 7 5 4 8
 2
5 8 4 7 1 2
0 8 6 2 4 9
 1
5 2 2 5 6 7
 2
6 5 2 7 1 3
3 7 8 1 0 9
 1
8 3 5 4 2 9
 3
0 1 2 3 4 5
6 7 8 9 1 2
3 4 5 6 7 8
 2
6 6 4 7 9 0
2 1 2 8 6 4
 3
2 3 4 5 6 7
3 4 5 6 7 8
9 1 2 3 4 5
 2
0 1 2 3 4 5
4 5 6 7 8 9
 3
2 7 3 6 4 5
0 2 1 9 4 8
8 6 9 5 4 0
 2
0 1 2 3 4 5
6 7 8 9 6 6
 2
1 7 2 0 4 3
5 2 3 6 1 0
 1
6 2 8 5 1 3
 3
5 4 8 1 6 7
0 9 3 5 8 6
2 4 7 8 1 3
 1
6 3 1 9 4 9
 3
0 1 9 1 0 8
9 9 3 5 6 2
9 3 9 9 7 3
 3
8 1 6 8 6 8
7 0 2 5 8 4
5 2 0 3 1 9
 3
2 0 1 3 4 5
6 7 8 9 1 1
3 4 5 6 6 7
 3
4 4 5 0 6 6
7 1 6 9 5 4
5 0 4 0 3 9
 2
0 1 2 3 4 5
9 8 7 6 5 4
 2
0 2 9 1 8 5
0 7 4 3 2 5
 2
2 3 9 1 6 7
2 5 4 3 0 6
 2
5 7 4 2 1 9
2 2 7 1 1 8
 1
3 9 1 7 4 5
 3
7 7 2 5 3 2
3 0 0 6 4 4
1 2 1 1 9 1
 1
7 9 5 0 4 6
 3
7 1 3 0 2 4
2 4 3 0 9 5
1 9 8 0 6 5
 1
4 3 8 9 2 3

3
 9
 9
 4
 2
 10
 10
 1
 4
 0
 2
 5
 0
 8
 2
 2
 10
 19
 3
 3
 2
 0
 5
 19
 3
 2
 1
 2
 1
 4
 2
 9
 5
 8
 1
 10
 7
 0
 5
 4
 3
 5
 9
 9
 29
 0
 0
 1
 8
 9
 21
 6
 21
 1
 8
 6
 1
 21
 6
 3
 2
 0
 0
 1
 0
 0
 0
 2
 0
 3
 0
 98
 2
 9
 9
 10
 9
 7
 3
 21
 1
 3
 32
 19
 1
 9
 5
 7
 2
 1
 7
 0
 65
 0

import java.io.*;
import java.util.HashSet;
import java.util.Set;

public class Task887B {

    public static void main(String... args) throws NumberFormatException,
            IOException {
        Solution.main(System.in, System.out);
    }

    static class Scanner {

        private final BufferedReader br;
        private String[] cache;
        private int cacheIndex;

        Scanner(InputStream is) {
            br = new BufferedReader(new InputStreamReader(is));
            cache = new String[0];
            cacheIndex = 0;
        }

        int nextInt() throws IOException {
            if (cacheIndex >= cache.length) {
                cache = br.readLine().split(" ");
                cacheIndex = 0;
            }
            return Integer.parseInt(cache[cacheIndex++]);
        }

        long nextLong() throws IOException {
            if (cacheIndex >= cache.length) {
                cache = br.readLine().split(" ");
                cacheIndex = 0;
            }
            return Long.parseLong(cache[cacheIndex++]);
        }

        String next() throws IOException {
            if (cacheIndex >= cache.length) {
                cache = br.readLine().split(" ");
                cacheIndex = 0;
            }
            return cache[cacheIndex++];
        }

        void close() throws IOException {
            br.close();
        }

    }

    static class Solution {

        public static void main(InputStream is, OutputStream os)
                throws NumberFormatException, IOException {
            PrintWriter pw = new PrintWriter(os);
            Scanner sc = new Scanner(is);

            long n = sc.nextLong();

            Set<Integer> possibleNumbers = new HashSet<>();

            Set<Integer> dices1 = new HashSet<>(6);
            Set<Integer> dices2 = new HashSet<>(6);
            Set<Integer> dices3 = new HashSet<>(6);

            for (int i = 0; i < 6; i++) {
                int tmp = sc.nextInt();
//                if (tmp == 6 || tmp == 9) {
//                    dices1.add(6);
//                    dices1.add(9);
//                }
                dices1.add(tmp);
            }

            if (n >= 2) {
                for (int i = 0; i < 6; i++) {
                    int tmp = sc.nextInt();
//                    if (tmp == 6 || tmp == 9) {
//                        dices2.add(6);
//                        dices2.add(9);
//                    }
                    dices2.add(tmp);
                }
            }

            if (n >= 3) {
                for (int i = 0; i < 6; i++) {
                    int tmp = sc.nextInt();
//                    if (tmp == 6 || tmp == 9) {
//                        dices3.add(6);
//                        dices3.add(9);
//                    }
                    dices3.add(tmp);
                }
            }

            for (Integer dice1 : dices1) {
                if (dice1 != 0) {
                    possibleNumbers.add(dice1);
                }
            }

            for (Integer dice2 : dices2) {
                if (dice2 != 0) {
                    possibleNumbers.add(dice2);
                }
            }

            for (Integer dice3 : dices3) {
                if (dice3 != 0) {
                    possibleNumbers.add(dice3);
                }
            }

            for (Integer dice1 : dices1) {
                for (Integer dice2 : dices2) {
                    if (dice1 != 0) {
                        possibleNumbers.add(dice1 * 10 + dice2);
                    }
                    if (dice2 != 0) {
                        possibleNumbers.add(dice2 * 10 + dice1);
                    }
                }
            }

            for (Integer dice2 : dices2) {
                for (Integer dice3 : dices3) {
                    if (dice2 != 0) {
                        possibleNumbers.add(dice2 * 10 + dice3);
                    }
                    if (dice3 != 0) {
                        possibleNumbers.add(dice3 * 10 + dice2);
                    }
                }
            }

            for (Integer dice1 : dices1) {
                for (Integer dice3 : dices3) {
                    if (dice1 != 0) {
                        possibleNumbers.add(dice1 * 10 + dice3);
                    }
                    if (dice3 != 0) {
                        possibleNumbers.add(dice3 * 10 + dice1);
                    }
                }
            }

            for (Integer dice1 : dices1) {
                for (Integer dice2 : dices2) {
                    for (Integer dice3 : dices3) {
                        if (dice1 != 0) {
                            possibleNumbers.add(dice1 * 100 + 10 * dice2 + dice3);
                            possibleNumbers.add(dice1 * 100 + 10 * dice3 + dice2);
                        }
                        if (dice2 != 0) {
                            possibleNumbers.add(dice2 * 100 + 10 * dice1 + dice3);
                            possibleNumbers.add(dice2 * 100 + 10 * dice3 + dice1);
                        }
                        if (dice3 != 0) {
                            possibleNumbers.add(dice3 * 100 + 10 * dice1 + dice2);
                            possibleNumbers.add(dice3 * 100 + 10 * dice2 + dice1);
                        }
                    }
                }
            }

            int retVal = 0;

            while (possibleNumbers.contains(retVal + 1)) {
                retVal++;
            }

            pw.println(retVal);

            pw.flush();
            sc.close();
        }
    }

}