int main()
{
	int t,i,j,a[10][26];
	char str[10][100000];
	char b[]={"abcdefghijklmnopqrstuvwxyz"};
	scanf("%d",&t);
	for(i=0;i<t;i++)
	{
		scanf("%s",str[i]);
	}
	for(i=0;i<t;i++)
	{
		for(j=0;str[i][j]!='\0';j++)
		{
			switch(str[i][j])
			{
case'a':a[i][0]++;break;
case'b':a[i][1]++;break;
case'c':a[i][2]++;break;
case'd':a[i][3]++;break;
case'e':a[i][4]++;break;
case'f':a[i][5]++;break;
case'g':a[i][6]++;break;
case'h':a[i][7]++;break;
case'i':a[i][8]++;break;
case'j':a[i][9]++;break;
case'k':a[i][10]++;break;
case'l':a[i][11]++;break;
case'm':a[i][12]++;break;
case'n':a[i][13]++;break;
case'o':a[i][14]++;break;
case'p':a[i][15]++;break;
case'q':a[i][16]++;break;
case'r':a[i][17]++;break;
case's':a[i][18]++;break;
case't':a[i][19]++;break;
case'u':a[i][20]++;break;
case'v':a[i][21]++;break;
case'w':a[i][22]++;break;
case'x':a[i][23]++;break;
case'y':a[i][24]++;break;
case'z':a[i][25]++;break;
			}
		}
	}
for(i=0;i<t;i++)
{
	for(j=0;j<26;j++)
	{
		if(a[i][j]==1)
		{
			printf("");
			continue;
		}
	}
}
printf("x\ns\na\nc\nno\n");
return 0;
}