#include<bits/stdc++.h>using namespace std;#define pb push_back#define mp make_pair#define se second#define fs first#define LL long long#define CLR(x) memset(x,0,sizeof x)#define MC(x,y) memcpy(x,y,sizeof(x))  #define SZ(x) ((int)(x).size())#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1 typedef pair<int,int> P;const double eps=1e-9;const int maxn=200100;const int mod=1e9+7;const int INF=1e9;int n;int mat[4][45];int dp[45][45][45][45];int DP(int *top,int st,int k){    int &m=dp[top[0]][top[1]][top[2]][top[3]];    if(m>=0) return m;    if(top[0]==n&&top[1]==n&&top[2]==n&&top[3]==n||k==5) return m=0;    for(int i=0;i<4;i++)    if(top[i]<n)    {        int bit=1<<mat[i][top[i]];        top[i]++;        if(bit&st) m=max(m,DP(top,st-bit,k-1)+1);        else       m=max(m,DP(top,st+bit,k+1));        top[i]--;    }    return m;}int main(){    while(~scanf("%d",&n)&&n)    {        memset(dp,-1,sizeof(dp));        for(int i=0;i<n;i++) scanf("%d%d%d%d",&mat[0][i],&mat[1][i],&mat[2][i],&mat[3][i]);        int top[5]={0};        printf("%d\n",DP(top,0,0));    }    return 0;}