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
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9 4 3 0 2 6
7 0 5 3 3 9
1 0 7 4 6 7
 1
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2 5 7 4 2 7
1 5 5 9 0 3
8 2 0 1 5 1
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1 7 8 6 0 9
3 2 1 7 4 9
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0 8 6 2 1 3
5 2 7 1 0 9
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5 3 2 9 8 2
0 7 4 8 1 8
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3 8 5 1 5 5
1 5 7 2 6 9
4 3 4 8 8 9
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5 1 2 3 0 8
3 6 7 4 9 2
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6 7 8 9 1 2
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8 0 6 5 1 4
7 1 0 8 3 4
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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
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6 7 8 9 0 1
3 3 4 5 6 7
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5 4 1 5 9 8
4 4 2 0 3 5
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0 3 8 4 7 6
1 4 5 8 7 0
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9 4 3 3 9 3
1 0 3 4 5 3
2 9 6 2 4 1
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1 2 3 7 8 9
9 8 7 1 2 3
7 9 2 3 1 8
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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
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8 6 9 0 7 2
6 9 3 2 5 7
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1 8 5 3 9 7
7 4 5 1 6 8
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5 8 4 7 1 2
0 8 6 2 4 9
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3 7 8 1 0 9
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0 1 2 3 4 5
6 7 8 9 1 2
3 4 5 6 7 8
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6 6 4 7 9 0
2 1 2 8 6 4
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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
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0 1 2 3 4 5
6 7 8 9 6 6
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1 7 2 0 4 3
5 2 3 6 1 0
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0 9 3 5 8 6
2 4 7 8 1 3
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9 3 9 9 7 3
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7 0 2 5 8 4
5 2 0 3 1 9
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3 4 5 6 6 7
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7 1 6 9 5 4
5 0 4 0 3 9
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0 1 2 3 4 5
9 8 7 6 5 4
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0 2 9 1 8 5
0 7 4 3 2 5
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2 3 9 1 6 7
2 5 4 3 0 6
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5 7 4 2 1 9
2 2 7 1 1 8
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3 0 0 6 4 4
1 2 1 1 9 1
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 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.Arrays;
import java.util.LinkedList;
import java.util.StringTokenizer;

public class Main {

    static MyScanner in;
    static PrintWriter out;

    public static void main(String[] args) throws IOException {
        in = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out), false);

        int n = in.nextInt();
        int[][] arr = in.next2Ints(n, 6);
        boolean[][] used = new boolean[n][3];

        int i;
        for (i = 1; i <= 1000; i++) {
            if (i == 1000)
                break;

            int a = i;
            int index = 0;
            while (a != 0) {
                int c = a % 10;
                a /= 10;

                for (int k = 0; k < n; k++)
                    used[k][index] = contains(arr[k], c);
                index++;
            }

            if (!can(used, 0, new boolean[n], index))
                break;
        }

        System.out.println(i - 1);
    }

    static boolean can(boolean[][] used, int pos, boolean[] visited, int cnt) {
        if (pos == cnt)
            return true;

        for (int i = 0; i < used.length; i++) {
            if (used[i][pos] && !visited[i]) {
                visited[i] = true;
                if (can(used, pos + 1, visited, cnt))
                    return true;
                visited[i] = false;
            }
        }

        return false;
    }

    static boolean contains(int[] arr, int k) {
        for (int a : arr)
            if (a == k)
                return true;
        return false;
    }


}

class MyScanner implements Closeable {

    public static final String CP1251 = "cp1251";

    private final BufferedReader br;
    private StringTokenizer st;
    private String last;

    public MyScanner() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }

    public MyScanner(String path) throws IOException {
        br = new BufferedReader(new FileReader(path));
    }

    public MyScanner(String path, String decoder) throws IOException {
        br = new BufferedReader(new InputStreamReader(new FileInputStream(path), decoder));
    }

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

    public String next() throws IOException {
        while (st == null || !st.hasMoreElements())
            st = new StringTokenizer(br.readLine());
        last = null;
        return st.nextToken();
    }

    public String next(String delim) throws IOException {
        while (st == null || !st.hasMoreElements())
            st = new StringTokenizer(br.readLine());
        last = null;
        return st.nextToken(delim);
    }

    public String nextLine() throws IOException {
        st = null;
        return (last == null) ? br.readLine() : last;
    }

    public boolean hasNext() {
        if (st != null && st.hasMoreElements())
            return true;

        try {
            while (st == null || !st.hasMoreElements()) {
                last = br.readLine();
                st = new StringTokenizer(last);
            }
        } catch (Exception e) {
            return false;
        }

        return true;
    }

    public String[] nextStrings(int n) throws IOException {
        String[] arr = new String[n];
        for (int i = 0; i < n; i++)
            arr[i] = next();
        return arr;
    }

    public String[] nextLines(int n) throws IOException {
        String[] arr = new String[n];
        for (int i = 0; i < n; i++)
            arr[i] = nextLine();
        return arr;
    }

    public int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    public int[] nextInts(int n) throws IOException {
        int[] arr = new int[n];
        for (int i = 0; i < n; i++)
            arr[i] = nextInt();
        return arr;
    }

    public Integer[] nextIntegers(int n) throws IOException {
        Integer[] arr = new Integer[n];
        for (int i = 0; i < n; i++)
            arr[i] = nextInt();
        return arr;
    }

    public int[][] next2Ints(int n, int m) throws IOException {
        int[][] arr = new int[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                arr[i][j] = nextInt();
        return arr;
    }

    public long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    public long[] nextLongs(int n) throws IOException {
        long[] arr = new long[n];
        for (int i = 0; i < n; i++)
            arr[i] = nextLong();
        return arr;
    }

    public long[][] next2Longs(int n, int m) throws IOException {
        long[][] arr = new long[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                arr[i][j] = nextLong();
        return arr;
    }

    public double nextDouble() throws IOException {
        return Double.parseDouble(next().replace(',', '.'));
    }

    public double[] nextDoubles(int size) throws IOException {
        double[] arr = new double[size];
        for (int i = 0; i < size; i++)
            arr[i] = nextDouble();
        return arr;
    }

    public double[][] next2Doubles(int n, int m) throws IOException {
        double[][] arr = new double[n][m];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                arr[i][j] = nextDouble();
        return arr;
    }

    public boolean nextBool() throws IOException {
        String s = next();
        if (s.equalsIgnoreCase("true") || s.equals("1"))
            return true;

        if (s.equalsIgnoreCase("false") || s.equals("0"))
            return false;

        throw new IOException("Boolean expected, String found!");
    }
}
