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 #include <iostream>
using namespace std;
const int maxn=1005;
const int M=28;
int map[M][M];
int chu[M],ru[M];
bool vis[M];
int n;
int sum;
void dfs(int s)
   {
 vis[s]=true;
sum++;
int i;
for(i=0;i<26;i++)
if(map[s][i]&&!vis[i])
dfs(i);
 }
int main()
{
int T;
scanf("%d",&T);
while(T--)
  {
memset(map,0,sizeof(map));
memset(chu,0,sizeof(chu));
memset(ru,0,sizeof(ru));
memset(vis,0,sizeof(vis));
scanf("%d",&n);
int i;
for(i=0;i<n;i++)
{
char word[maxn];
scanf("%s",&word);
int len=strlen(word);
map[word[0]-'a'][word[len-1]-'a']=1;
chu[word[0]-'a']++;
ru[word[len-1]-'a']++;
 }
int n0=0,n1=0,n2=0,n3=0;
int s=-1,e=-1;
for(i=0;i<26;i++)
{
if(chu[i]==0&&ru[i]==0)
continue;
n0++;
if((ru[i]-chu[i])==1)
n2++;
if((chu[i]-ru[i])==0)
n3++;
if((chu[i]-ru[i])==1)
{
s=i;
n1++;
}
e=i;
}
sum=0;
if(s!=-1)
dfs(s);
else
dfs(e);
if(sum!=n0)
{
printf("The door cannot be opened.\n");
continue;
}
if( (n1==1&&n2==1&&n3==(n0-2)) || (n0==n3) )
printf("Ordering is possible.\n");
else
printf("The door cannot be opened.\n");
}
return 0;
}
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