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

int compare( char *c1, char *c2 )
{
    int i=0, j=0;
    for( i=0; i<8; i++ )
    {
	if( *c1 != *c2 )
	    j++;
	
	c1++;
	c2++;
    }
    
    return j;
}

int main1(int n) {
    int score,i,j,minScore=99999, minInd;
    char words[2000][8];
    
    for( i=0; i<n; i++ )
    {
	scanf( "%s", words[i] );
    }
    
    for( i=0; i<n; i++ )
    {
	score = 0;
	for( j=0; j<n; j++ )
	{
	    score += compare( words[i], words[j] );
	    if( score >= minScore )
		break;
	}
	
	if( j >= n && score < minScore )
	{
	    minScore = score;
	    minInd = i;
	}
    }
	
    printf( "The highest possible quality is 1/%d.\n", minScore );
    return 0;
}

int main()
{
    int n;

    while( scanf( "%d", &n ), n > 0 )
	main1( n );
    
return 0;

}