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.util.*;
import java.io.*;
import static java.lang.Math.*;

public class q2 {
    
    static class Scan {

        private final InputStream inputStream;
	private final byte[] buffer = new byte[1024];
	private int currentChar;
	private int numChars;
	private SpaceCharFilter filter;

	public Scan () {
            inputStream = System.in;
	}

	public int read () {
            if (numChars==-1)
		throw new InputMismatchException();

            if (currentChar >= numChars) {
		currentChar = 0;
		try {
                    numChars = inputStream.read(buffer);
		}
		catch (IOException e) {
                    throw new InputMismatchException();
		}
				
		if (numChars <= 0)				
                    return -1;
            }
            return buffer[currentChar++];
	}
	 
	public String nextLine () {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String str = "";
            
            try {
                str = br.readLine();
            }
            catch (IOException e) {
            }
            return str;
	}
	
        public int nextInt () {	
            int ch = read();
			
            while (isSpaceChar(ch)) 
		ch = read();
			
            int sgn = 1;
			
            if (ch == '-') {
		sgn = -1;
                ch = read();
            }
			
            int res = 0;
            do {
		if (ch < '0' || ch > '9') 
                    throw new InputMismatchException();
		res *= 10;
		res += ch - '0';
		ch = read();
            }
            while (!isSpaceChar(ch)); 
			
            return res * sgn;
	}
		
	public long nextLong () {
            int ch = read();
            
            while (isSpaceChar(ch))
		ch = read();
            
            int sgn = 1;
            
            if (ch == '-') {
		sgn = -1;
		ch = read();
            }
            
            long res = 0;
			
            do {
                if (ch < '0' || ch > '9')
                    throw new InputMismatchException();
		res *= 10;
		res += ch - '0';
		ch = read();
            }
            while (!isSpaceChar(ch));
            
            return res * sgn;
	}
		
	public double nextDouble () {
            int ch = read();
		
            while (isSpaceChar(ch))
		ch = read();
            
            int sgn = 1;
            if (ch == '-') {
		sgn = -1;
		ch = read();
            }
	
            double res = 0;
            while (!isSpaceChar(ch) && ch != '.') {
		if (ch == 'e' || ch == 'E')
                    return res * Math.pow(10, nextInt());
		if (ch < '0' || ch > '9')
                    throw new InputMismatchException();
		res *= 10;
		res += ch - '0';
		ch = read();
            }
            if (ch == '.') {
		ch = read();
		double m = 1;
		while (!isSpaceChar(ch)) {
                    if (ch == 'e' || ch == 'E')
			return res * Math.pow(10, nextInt());
                    if (ch < '0' || ch > '9')
                    	throw new InputMismatchException();
                    m /= 10;
                    res += (ch - '0') * m;
                    ch = read();
		}
            }
	
            return res * sgn;
	}
		
	public String readString () {
            int ch = read();
            while (isSpaceChar(ch))
		ch = read();
	
            StringBuilder res = new StringBuilder();
	
            do {
		res.appendCodePoint(ch);
		ch = read();
            } 
            while (!isSpaceChar(ch));
			
            return res.toString();
	}
	 
	public boolean isSpaceChar (int ch) {
            if (filter != null)
		return filter.isSpaceChar(ch);
            return ch == ' ' || ch == '\n' || ch == '\r' || ch == '\t' || ch == -1;
	}
	 
	public String next () {
            return readString();
	}

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
	}
    }
    
    static class Print {
        private final BufferedWriter bw;
        
        public Print () {
            this.bw=new BufferedWriter(new OutputStreamWriter(System.out));
        }
        
        public void print (Object object)throws IOException {
            bw.append(""+object);
        }
        
        public void println (Object object)throws IOException {
            print(object);
            bw.append("\n");
        }
        
        public void close () throws IOException {
            bw.close();
        }
    }
    
    private static void readArray (int[] arr, Scan scan) {
        for (int i = 0; i < arr.length; i++) {
            arr[i] = scan.nextInt();
        }
    }
    
    private static void read2DArray (int[][] arr, Scan scan) {
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                arr[i][j] = scan.nextInt();
            }
        }
    }
    
    private static void printArray (int[] arr, char ch, Print pr) throws IOException {
        for (int i = 0; i < arr.length; i++) {
            pr.print(arr[i] + "" + ch);
        }
    }
    
    private static void print2DArray (int[][] arr, Print pr) throws IOException {
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                pr.print(arr[i][j] + " ");
            }
            pr.println("");
        }
    }
    
    private static void sort2DArray (int[][] arr) {
        
        Arrays.sort (arr, new Comparator<int[]>() {
            public int compare (int[] a, int[] b) {
                return Integer.compare(a[0], b[0]);
            }
        });
    }
    
    public static void main (String[] args) throws IOException {
        Scan sc = new Scan();
        Print pr = new Print();
        
        int n, i, j, k, l;
        n=sc.nextInt();
        
        int arr[][] = new int[n][6];
        
        read2DArray(arr, sc);
        
        int a[] = new int[1000];
        
        if(n==1) {
            for(j=0;j<6;j++) {
                a[arr[0][j]]=1;
            }
        }
        else if(n==2) {
            for(i=0;i<n;i++) {
                for(j=0;j<6;j++) {
                    a[arr[i][j]]=1;
                }
            }
            for(i=0;i<n;i++) {
                for(j=0;j<6;j++) {
                    for(k=0;k<6;k++) {
                        a[arr[i][j]*10+arr[(i+1)%2][k]]=1;
                    }
                }
            }
        }
        else {
           for(i=0;i<n;i++) {
                for(j=0;j<6;j++) {
                    a[arr[i][j]]=1;
                }
            } 
           for(i=0;i<n;i++) {
                for(j=0;j<6;j++) {
                    for(k=0;k<6;k++) {
                        a[arr[i][j]*10+arr[(i+1)%3][k]]=1;
                        a[arr[i][j]*10+arr[(i+2)%3][k]]=1;
                    }
                }
            }
           for(i=0;i<n;i++) {
               for(j=0;j<6;j++) {
                   for(k=0;k<6;k++) {
                       for(l=0;l<6;l++) {
                           a[arr[i][j]*100+arr[(i+1)%3][k]*10+arr[(i+2)%3][l]]=1;
                           a[arr[i][j]*100+arr[(i+2)%3][k]*10+arr[(i+1)%3][l]]=1;
                       }
                   }
               }
           }
        }
        
        for(i=1;i<1000;i++) {
            if(a[i]!=1) {
                pr.println(i-1);
                pr.close();
                return;
            }
        }
        
        pr.println("999");
        
        pr.close();
    }
    
}