#pragma comment(linker, "/STACK:102400000, 102400000")
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<iostream>
#include<sstream>
#include<iterator>
#include<algorithm>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<stack>
#include<deque>
#include<queue>
#include<list>
#define Min(a, b) ((a < b) ? a : b)
#define Max(a, b) ((a < b) ? b : a)
typedef long long ll;
typedef unsigned long long llu;
const int INT_INF = 0x3f3f3f3f;
const int INT_M_INF = 0x7f7f7f7f;
const ll LL_INF = 0x3f3f3f3f3f3f3f3f;
const ll LL_M_INF = 0x7f7f7f7f7f7f7f7f;
const int dr[] = {0, 0, -1, 1, -1, -1, 1, 1};
const int dc[] = {-1, 1, 0, 0, -1, 1, -1, 1};
const int MOD = 1e9 + 7;
const double pi = acos(-1.0);
const double eps = 1e-8;
const int MAXN = 1000 + 10;
const int MAXT = 10000 + 10;
using namespace std;
char s[MAXN];
int fa[30];
int in[30];
int out[30];
int Find(int x){return fa[x] = (x == fa[x]) ? x : Find(fa[x]);
}
int main(){int T;scanf("%d", &T);while(T--){for(int i = 0; i <= 25; ++i){fa[i] = i;}memset(in, 0, sizeof in);memset(out, 0, sizeof out);int n;scanf("%d", &n);for(int i = 0; i < n; ++i){scanf("%s", s);int len = strlen(s);int x = s[0] - 'a';int y = s[len - 1] - 'a';++in[y];++out[x];int tx = Find(x);int ty = Find(y);fa[ty] = tx;//首字母是尾字母的祖先
        }bool ok = true;int cnt = 0;for(int i = 0; i < 26; ++i){//统计连通块个数if((in[i] || out[i]) && fa[i] == i){++cnt;}}if(cnt > 1) ok = false;//图不连通int num1 = 0;//入度比出度大1的结点数int num2 = 0;//出度比入度大1的结点数for(int i = 0; i < 26; ++i){if(!ok) break;if(in[i] != out[i]){if(in[i] - out[i] == 1) ++num1;else if(out[i] - in[i] == 1) ++num2;else{ok = false;break;}}}if(ok){if(!((num1 == 0 && num2 == 0) || (num1 == 1 && num2 == 1))) ok = false;}if(!ok){printf("The door cannot be opened.\n");}else{printf("Ordering is possible.\n");}}return 0;
}