#include <stdio.h>

int main() {
    int n;
    char o[10];
    char d[10];
    scanf("%i", &n);
    while (n != 0) {
	int sum = 0;
	scanf("%s", o);
	for (int i=0; i<n - 1; i++) {
	    scanf("%s", d);
	    for (int j=0; j<7; j++) {
		if (o[j] != d[j]) {
		    sum++;
		}
	    }
	}
	printf("The highest possible quality is 1/%i.\n", sum);
	scanf("%i", &n);
    }
    return 0;
}