#include<cstdio>

 #include<iostream>

 #include<algorithm>

 #include<cstring>

 #include<cmath>

 #include<queue>

 #include<map>

 using namespace std;

 typedef long long ll;

 #define cl(a) memset(a,0,sizeof(a))

 #define ts printf("*****\n");

 #define MAXN 202

 vector<int>EV[MAXN];

 int linker[MAXN];

 bool used[MAXN];

 int uN;

 int matchs[MAXN],cnt[MAXN];

 bool dfs(int u)

 {

     int i;

     for(i=;i<EV[u].size();i++)

     {

         int v=EV[u][i];

         if(!used[v])

         {

             used[v]=true;

             if(linker[v]==-||dfs(linker[v]))

             {

                 linker[v]=u;

                 return true;

             }

         }

     }

     return false;

 }

 int hungary()

 {

     int res=;

     int u;

     memset(linker,-,sizeof(linker));

     for(u=;u<=uN;u++)

     {

         memset(used,false,sizeof(used));

         if(dfs(u))  res++;

     }

     return res;

 }

 bool judge(int x,int y)     //交叉染色法判断二分图

 {

     int i;

     for(i=;i<EV[x].size();i++)

     {

         if(cnt[EV[x][i]]==)

         {

             cnt[EV[x][i]]=-*y;

             matchs[EV[x][i]]=true;

             if(!judge(EV[x][i],-*y)) return false;

         }

         else if(cnt[EV[x][i]]==y)  return false;

     }

     return true;

 }

 bool matched()

 {

     int i;

     memset(matchs,false,sizeof(matchs));

     for(i=;i<=uN;i++)

     {

         if(EV[i].size()&&!matchs[i])

         {

             memset(cnt,,sizeof(cnt));

             cnt[i]=-;

             matchs[i]=true;

             if(!judge(i,-)) return false;

         }

     }

     return true;

 }

 int g[MAXN][MAXN];

 int main()

 {

     int m,n;

     int i,j;

     int u,v;

     #ifndef ONLINE_JUDGE

     freopen("1.in","r",stdin);

     #endif

     while(scanf("%d",&uN)!=EOF)

     {

         n=uN;

         for(i=;i<=uN;i++)

           if(EV[i].size())  EV[i].clear();

         cl(g);

         int id;

         for(i=;i<=n;i++)

         {

             while(scanf("%d",&id)!=EOF&&id)

             {

                 g[i][id]=;

             }

         }

         for(i=;i<=n;i++)

         {

             for(j=i+;j<=n;j++)

             {

                 if(!g[i][j]||!g[j][i])

                 {

                     EV[i].push_back(j);

                     EV[j].push_back(i);

                 }

             }

         }

          if(matched())

                   printf("YES\n");

          else  printf("NO\n");

     }

     return ;

 }