#include <stdio.h>

#define MAX 5000000

int check(int);
int eq();

int n, digit[10], memo[10], table[MAX + 1];

int main(void) {
	scanf("%d", &n);
	int i;
	for(i = 0; i < n; i++) {
		int temp;
		scanf("%d", &temp);
		digit[temp] = 1;
	}
	
	table[1] = 1;
	int max = 0, counter = 0;
	for(i = 1; i <= MAX; i++) {
		if(table[i] == 0) {
			int m = i * 2;
			while(m <= MAX) {
				table[m] = 1;
				m += i;
			}
			if( ! check(i) ) {
				counter = 0;
				int j;
				for(j = 0; j < 10; j++) { memo[j] = 0; }
				continue;
			}
		}
		counter++;
		if( eq() ) { max = (max < counter) ? counter : max; }
	}
	
	printf("%d\n", max - 1);
	
	return 0;
}

int check(int i) {
	while(i) {
		if(digit[i % 10] == 0) { return 0; }
		memo[i % 10] = 1;
		i /= 10;
	}
	return 1;
}

int eq() {
	int i;
	for(i = 0; i < 10; i++) {
		if(digit[i] != memo[i]) { return 0; }
	}
	return 1;
}