#include <stdio.h>
#include <string.h>

char radky[2000][7];

int total = 0;
int _lisi;

void printit()
{
	printf("The highest possible quality is 1/%i.\n", _lisi);
}

void vyresto()
{
	int radek,sloupec, _radek;
	int higher;
	
	_lisi = 0;
	higher = 0;
	for(_radek = 1; _radek < total; _radek++)
	{
		for (sloupec = 0; sloupec < 7; sloupec++)
		{
			if (radky[0][sloupec] != radky[_radek][sloupec]) _lisi++;
		}
	}
}

int main()
{
	int i,k;
	char buffer[8] = "\0";

	for (;;){
		gets(buffer);

		sscanf(buffer, "%i", &total);

		if (total == 0)
			return 0;

		for (i = 0; i < total; i++)
		{
			for (k = 0; k< 7; k++)
				radky[i][k] = getchar();

			getchar();
		}
		vyresto();
		printit();
	} 

	return 0;
}