1 #include <iostream>

 2 #include <cstdio>

 3 #include <cstring>

 4 using namespace std;

 5 #define Max 30

 6 #define MaxLen 1010

 7 int T,n,Bgn;

 8 int Edge[Max][Max],Chu[Max],Ru[Max];

 9 bool vis[Max];

10 char str[MaxLen];

11 inline void Get_int(int &Ret)

12 {

13     char ch;

14     bool flag=false;

15     for(;ch=getchar(),ch<'0'||ch>'9';)

16         if(ch=='-')

17             flag=true;

18     for(Ret=ch-'0';ch=getchar(),ch>='0'&&ch<='9';Ret=Ret*10+ch-'0');

19     flag&&(Ret=-Ret);

20 }

21 inline void Read()

22 {

23     Get_int(n);

24     memset(vis,false,sizeof(vis));

25     memset(Chu,0,sizeof(Chu));

26     memset(Ru,0,sizeof(Ru));

27     memset(Edge,0,sizeof(Edge));

28     int i,u,v,Len;

29     for(i=1;i<=n;i++)

30     {

31         do

32         {

33             scanf("%s",str);

34             Len=strlen(str);

35         }while(!Len);

36         u=str[0]-'a'+1; v=str[Len-1]-'a'+1;

37         //if(u==v) continue;

38         Edge[u][v]++;Edge[v][u]++;

39         Chu[u]++;Ru[v]++;

40         vis[u]=vis[v]=true;

41     }

42     Bgn=u;

43 }

44 void Dfs(int u)

45 {

46     vis[u]=false;

47     for(int i=1;i<=26;i++)

48         if(Edge[u][i]&&vis[i])

49             Dfs(i);

50 }

51 inline bool Solve()

52 {

53     int i,ch=0,ru=0;

54     Dfs(Bgn);

55     for(i=1;i<=26;i++)

56     {

57         if(vis[i])

58             return false;

59         if(Chu[i]!=Ru[i])

60         {

61             if(Chu[i]-Ru[i]==1)

62                 ch++;

63             else if(Ru[i]-Chu[i]==1)

64                 ru++;

65             else

66                 return false;

67         }

68     }

69     if((ch==1&&ru==1)||(ch==0&&ru==0))

70         return true;

71     return false;

72 }

73 int main()

74 {

75     Get_int(T);

76     while(T--)

77     {

78         Read();

79         if(Solve())

80             printf("Ordering is possible.\n");

81         else

82             printf("The door cannot be opened.\n");

83     }

84     return 0;

85 }