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

// Bismillahirrahmanir Rahim
#include<bits/stdc++.h>
#define nl printf("\n")
#define sp printf(" ")
#define rep(i,a,b) for(i=a;i<=b;i++)
#define rev(i,a,b) for(i=a;i>=b;i--)
#define fil freopen("input.txt","r",stdin)
#define pf printf
#define sf scanf
using namespace std;

typedef long long l;
typedef unsigned long long ul;

//// Ordered set> Finding nth position element in a set in logn complexity
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<typename T> using orderset = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
////*X.find_by_order(1)
////X.order_of_key(-5)

#define pi acos(-1.0)
#define mp make_pair
#define pb push_back
#define p_q priority_queue

int inline in(){int x;sf("%d",&x);return x;}
l inline lin(){l x;sf("%lld",&x);return x;}
void P(l x){pf("%lld",x);}
void Pi(int x){pf("%d",x);}

#define C(i) pf("Case %lld: ",i)
#define Ci(i) pf("Case %d: ",i)

#define Inf 0x7f7f7f
#define mod 1000000007

#define ms(a,b) memset(a,b,sizeof(a))
#define DBG pf("I am here\n")

#define dis( a ,b ) abs( a - b )
#define dis2d( x1 ,y1 ,x2 ,y2 )    sqrt( ( x1 - x2 ) * ( x1 - x2 ) + ( y1 - y2 ) * ( y1 - y2 ) )
#define dis3d( x1 ,y1 ,z1 ,x2 ,y2 ,z2 )    sqrt( ( x1 - x2 ) * ( x1 - x2 ) + ( y1 - y2 ) * ( y1 - y2 ) + ( z1 - z2 ) * ( z1 - z2 ) )

#define valid(nx,ny,r,c) nx>=1&&nx<=r && ny>=1&&ny<=c

#define ck_bt( v , p ) ( ( v >> p ) & 1 )

char tochar( int x ){return x + '0' ;}
int toint( char x ){return x - '0' ;}

l fx[]= {0,0,-1,1,-1,-1,1,1};
l fy[]= {-1,1,0,0,-1,1,-1,1};

l dx[]= {0,0,-1,1};
l dy[]= {-1,1,0,0};

l n , m ;

//l a[200010] ;
//l L[200010] ;
//l I[200010] ;
//
//l lis(  )
//{
//    I[0] = -LLONG_MAX ;
//    l i ;
//    rep( i , 1 , n )
//    {
//        I[i] = LLONG_MAX ;
//    }
//    l lisLength = 0 ;
//    for( i = 1 ; i <= n ; i ++ )
//    {
//        l left , right , mid ;
//        left = 0 , right = lisLength ;
//        while( left <= right )
//        {
//            mid = left + ( right - left ) / 2 ;
//            if( I[mid] < a[i] )
//            {
//                left = mid + 1 ;
//            }
//            else
//            {
//                right = mid - 1 ;
//            }
//        }
//        L[i] = left ;
//        I[left] = a[i] ;
//        if( left > lisLength )
//            lisLength = left ;
//    }
//
//    return lisLength ;
//}

//#define mod
//
//l bm(l b, l p)
//{
//    l namira;
//    if(p==0)return 1;
//    if(p%2==0)
//    {
//        namira=bm(b,p/2);
//        return ((namira%mod)*(namira%mod))%mod;
//    }
//    else
//    {
//        return ((b%mod)*(bm(b,p-1)%mod))%mod;
//    }
//}


char s[1000] ;
l a[5][20] ;

set<l>st ;
set<l>::iterator it ;


int main()
{

    l i , j , j1 , k ;

    n = lin() ;
    rep( i , 1 , n )
    {
        rep( j , 1 , 6 )
        {
            a[i][j] = lin() ;
        }
    }
    if( n == 1 )
    {
        rep( i , 1 , 6 )
        {


            if( a[i][j] )
                st.insert( a[1][i] ) ;
        }
    }
    else if( n == 2 )
    {
        rep( k , 1 , n )
        {
            if( k == 1 )
            {
                rep( i , 1 , n )
                {
                    rep( j , 1 , 6 )
                    {
                        if( a[i][j] )
                            st.insert( a[i][j] ) ;
                    }
                }
            }
            else
            {
                rep( i , 1 , 6 )
                {
                    if( a[1][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[1][i] * 10 + a[2][j] ;
                            st.insert( x ) ;
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    if( a[2][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[2][i] * 10 + a[1][j] ;
                            st.insert( x ) ;
                        }
                    }
                }
            }
        }
    }
    else
    {
        rep( k , 1 , n )
        {
            if( k == 1 )
            {
                rep( i , 1 , n )
                {
                    rep( j , 1 , 6 )
                    {
                        if( a[i][j] )
                            st.insert( a[i][j] ) ;
                    }
                }
            }
            else if( k == 2 )
            {
                rep( i , 1 , 6 )
                {
                    if( a[1][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[1][i] * 10 + a[2][j] ;
                            st.insert( x ) ;
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    if( a[2][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[2][i] * 10 + a[1][j] ;
                            st.insert( x ) ;
                        }
                    }
                }



                rep( i , 1 , 6 )
                {
                    if( a[1][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[1][i] * 10 + a[3][j] ;
                            st.insert( x ) ;
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    if( a[3][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[3][i] * 10 + a[1][j] ;
                            st.insert( x ) ;
                        }
                    }
                }




                rep( i , 1 , 6 )
                {
                    if( a[2][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[2][i] * 10 + a[3][j] ;
                            st.insert( x ) ;
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    if( a[3][i] != 0 )
                    {
                        rep( j , 1 , 6 )
                        {
                            l x = a[3][i] * 10 + a[2][j] ;
                            st.insert( x ) ;
                        }
                    }
                }


            }
            else
            {
                rep( i , 1 , 6 )
                {
                    rep( j , 1 , 6 )
                    {
                        rep( j1 , 1 , 6 )
                        {
                            if( a[1][i] != 0 )
                            {
                                l x = a[1][i] * 100 + a[2][j] * 10 + a[3][j1] ;
                                st.insert( x ) ;
                            }
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    rep( j , 1 , 6 )
                    {
                        rep( j1 , 1 , 6 )
                        {
                            if( a[3][i] != 0 )
                            {
                                l x = a[3][i] * 100 + a[2][j] * 10 + a[1][j1] ;
                                st.insert( x ) ;
                            }
                        }
                    }
                }




                rep( i , 1 , 6 )
                {
                    rep( j , 1 , 6 )
                    {
                        rep( j1 , 1 , 6 )
                        {
                            if( a[1][i] != 0 )
                            {
                                l x = a[1][i] * 100 + a[3][j] * 10 + a[2][j1] ;
                                st.insert( x ) ;
                            }
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    rep( j , 1 , 6 )
                    {
                        rep( j1 , 1 , 6 )
                        {
                            if( a[2][i] != 0 )
                            {
                                l x = a[2][i] * 100 + a[3][j] * 10 + a[1][j1] ;
                                st.insert( x ) ;
                            }
                        }
                    }
                }






                rep( i , 1 , 6 )
                {
                    rep( j , 1 , 6 )
                    {
                        rep( j1 , 1 , 6 )
                        {
                            if( a[2][i] != 0 )
                            {
                                l x = a[2][i] * 100 + a[1][j] * 10 + a[3][j1] ;
                                st.insert( x ) ;
                            }
                        }
                    }
                }
                rep( i , 1 , 6 )
                {
                    rep( j , 1 , 6 )
                    {
                        rep( j1 , 1 , 6 )
                        {
                            if( a[3][i] != 0 )
                            {
                                l x = a[3][i] * 100 + a[1][j] * 10 + a[2][j1] ;
                                st.insert( x ) ;
                            }
                        }
                    }
                }


            }
        }
    }

    l d = 0 ;

    for( it = st.begin() ; it != st.end() ; it ++ )
    {
        if( *it != ( d + 1 ) )
            break ;
        d ++ ;
    }
    P( d ) ; nl ;

    return 0;
}
