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 java.lang.Math.*;

public class MainA
{
	static int mod = (int) 1e9 + 7;
	
	public static void main(String[] args) throws java.lang.Exception
	{
		InputReader in = new InputReader(System.in);
		PrintWriter out=new PrintWriter(System.out);
		int n=in.nextInt();
		HashSet<Character> hs[]=new HashSet[n];
		for(int i=0;i<n;i++)hs[i]=new HashSet();
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<6;j++)
			{
				int a=in.nextInt();
				String st=Integer.toString(a);
				hs[i].add(st.charAt(0));
			}
		}
		int flag=0;
		for(int i=0;i<1000;i++)
		{
			if(i<10)
			{
				String s=Integer.toString(i);
				int fla=-1;
				for(int j=0;j<n;j++)
				{
					if(hs[j].contains(s.charAt(0)))
					{
						fla=1;
						break;
					}
				}
				if(fla==-1)
				{
					flag=i;
					break;
				}
			}
			else if(i<100 && n>=2)
			{
				int fla=-1;
				String s=Integer.toString(i);
				if(n==2)
				{
					if((hs[0].contains(s.charAt(0))&& hs[1].contains(s.charAt(1)))||(hs[1].contains(s.charAt(0))&& hs[0].contains(s.charAt(1))))
					{
						fla=1;
					}
					else 
					{
						flag=i;
						break;
					}
				}
				else if(n==3)
				{
					//out.println(i +" "+s.charAt(0)+" "+s.charAt(1)+" "+hs[0].contains(s.charAt(0)+" "+hs[1].contains(s.charAt(1))));
					if((hs[0].contains(s.charAt(0))&& (hs[1].contains(s.charAt(1))||hs[2].contains(s.charAt(1))))||(hs[1].contains(s.charAt(0))&& (hs[0].contains(s.charAt(1))||hs[2].contains(s.charAt(1))))||(hs[2].contains(s.charAt(0))&& (hs[1].contains(s.charAt(1))||hs[0].contains(s.charAt(1)))))
					{
						fla=1;
						//out.println("sss");
					}
					else 
					{
						flag=i;
						break;
					}
				}
				if(i==99 && (n==2 && flag==0))
				{
					flag=100;
					break;
				}
				
			}
			else if(n==3)
			{
				String s=Integer.toString(i);
				if(hs[0].contains(s.charAt(0))&&((hs[1].contains(s.charAt(1))&&hs[2].contains(s.charAt(2)))||(hs[2].contains(s.charAt(1))&&hs[1].contains(s.charAt(2)))))
				{
					
				}
				else if(hs[1].contains(s.charAt(0))&&((hs[0].contains(s.charAt(1))&&hs[2].contains(s.charAt(2)))||(hs[2].contains(s.charAt(1))&&hs[0].contains(s.charAt(2)))))
				{
					
				}
				else if(hs[2].contains(s.charAt(0))&&((hs[1].contains(s.charAt(1))&&hs[0].contains(s.charAt(2)))||(hs[0].contains(s.charAt(1))&&hs[1].contains(s.charAt(2)))))
				{
					
				}
				else 
				{
					flag=i;
					break;
				}
				if(i==999 && (n==3 && flag==0))
				{
					flag=1000;
					break;
				}
			}
		}
		if(flag==0)
		out.println(flag);
		else out.println(flag-1);
		out.close();
	}

	public static long add(long a,long b)
	{
		return (a+b)%mod;
	}
	public static long mul(long a,long b)
	{
		return (a*b)%mod;
	}
	
	public static long sub(long a,long b)
	{
		return (a-b+mod)%mod;
	}
	static class Pairs implements Comparable<Pairs>
	{
		int x;
		int y;
		
		
		Pairs(int a, int b)
		{
			x = a;
			y = b;
			
		}

		@Override
		public boolean equals(Object o)
		{
			Pairs other=(Pairs)o;
			return x==other.x && y==other.y;
		}
		@Override
		public int compareTo(Pairs o)
		{
			// TODO Auto-generated method stub
			return Integer.compare(x,o.x);
		}
		@Override
		public int hashCode()
		{
			return  Objects.hash(x,y);
		}

	}

	public static void debug(Object... o) 
	{
		System.out.println(Arrays.deepToString(o));
	}

	public static boolean isPal(String s) 
	{
		for (int i = 0, j = s.length() - 1; i <= j; i++, j--)
		{
			if (s.charAt(i) != s.charAt(j))
				return false;
		}
		return true;
	}

	public static String rev(String s)
	{
		StringBuilder sb = new StringBuilder(s);
		sb.reverse();
		return sb.toString();
	}

	public static long gcd(long x, long y)
	{
		if (y == 0)
			return x;
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}

	public static int gcd(int x, int y)
	{
		if(y==0)
			return x;
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}

	public static long gcdExtended(long a, long b, long[] x) 
	{

		if (a == 0) 
		{
			x[0] = 0;
			x[1] = 1;
			return b;
		}
		long[] y = new long[2];
		long gcd = gcdExtended(b % a, a, y);

		x[0] = y[1] - (b / a) * y[0];
		x[1] = y[0];

		return gcd;
	}

	
	

	public static long max(long a, long b) 
	{
		if (a > b)
			return a;
		else
			return b;
	}

	public static long min(long a, long b)
	{
		if (a > b)
			return b;
		else
			return a;
	}

	public static long[][] mul(long a[][], long b[][])
	{
		long c[][] = new long[2][2];
		c[0][0] = a[0][0] * b[0][0] + a[0][1] * b[1][0];
		c[0][1] = a[0][0] * b[0][1] + a[0][1] * b[1][1];
		c[1][0] = a[1][0] * b[0][0] + a[1][1] * b[1][0];
		c[1][1] = a[1][0] * b[0][1] + a[1][1] * b[1][1];

		return c;
	}

	public static long[][] pow(long n[][], long p, long m)
	{
		long result[][] = new long[2][2];
		result[0][0] = 1;
		result[0][1] = 0;
		result[1][0] = 0;
		result[1][1] = 1;

		if (p == 0)
			return result;
		if (p == 1)
			return n;
		while (p != 0)
		{
			if (p % 2 == 1)
				result = mul(result, n);
			//System.out.println(result[0][0]);
			for (int i = 0; i < 2; i++)
			{
				for (int j = 0; j < 2; j++)
				{
					if (result[i][j] >= m)
						result[i][j] %= m;
				}
			}

			p >>= 1;
			n = mul(n, n);
			// System.out.println(1+" "+n[0][0]+" "+n[0][1]+" "+n[1][0]+" "+n[1][1]);
			for (int i = 0; i < 2; i++) 
			{
				for (int j = 0; j < 2; j++)
				{
					if (n[i][j] >= m)
						n[i][j] %= m;
				}
			}
		}
		return result;
	}
	public static long pow(long n,long p, long m)
	{
		long result=1;
		if(p==0)return 1;
		if(p==1)return n%m;
		while(p!=0)
		{
			if(p%2==1)result=(result*n)%m;
			p >>=1;
			n=(n*n)%m;
		}
		return result;
	}
	public static long pow(long n, long p) 
	{
		long result = 1;
		if (p == 0)
			return 1;
		if (p == 1)
			return n;
		while (p != 0)
		{
			if (p % 2 == 1)
				result *= n;
			p >>= 1;
			n *= n;
		}
		return result;
	}

	static class InputReader {

		private final InputStream stream;
		private final byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;

		public InputReader(InputStream stream)
		{
			this.stream = stream;
		}

		public int snext()
		{
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars)
			{
				curChar = 0;
				try 
				{
					snumChars = stream.read(buf);
				}
				catch (IOException e)
				{
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public int nextInt()
		{
			int c = snext();
			while (isSpaceChar(c))
			{
				c = snext();
			}
			int sgn = 1;
			if (c == '-')
			{
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			}
			while (!isSpaceChar(c));
			return res * sgn;
		}

		public long nextLong()
		{
			int c = snext();
			while (isSpaceChar(c))
			{
				c = snext();
			}
			int sgn = 1;
			if (c == '-') 
			{
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do 
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			}
			while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n)
		{
			int a[] = new int[n];
			for (int i = 0; i < n; i++)
			{
				a[i] = nextInt();
			}
			return a;
		}

		public long[] nextLongArray(int n)
		{
			long a[] = new long[n];
			for (int i = 0; i < n; i++) 
			{
				a[i] = nextInt();
			}
			return a;
		}

		public String readString()
		{
			int c = snext();
			while (isSpaceChar(c))
			{
				c = snext();
			}
			StringBuilder res = new StringBuilder();
			do 
			{
				res.appendCodePoint(c);
				c = snext();
			} 
			while (!isSpaceChar(c));
			return res.toString();
		}

		public String nextLine()
		{
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do
			{
				res.appendCodePoint(c);
				c = snext();
			}
			while (!isEndOfLine(c));
			return res.toString();
		}

		public boolean isSpaceChar(int c) 
		{
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c)
		{
			return c == '\n' || c == '\r' || c == -1;
		}

		public interface SpaceCharFilter 
		{
			public boolean isSpaceChar(int ch);
		}
	}
}