/* This Code is Submitted by wywcgs for Problem 1062 on 2006-10-04 at 13:39:49 */
#include <cstdio>
#include <algorithm>
using namespace std;
 
int main()
{
    int n;
    int i, j;
    long maxi, mini, num[50000], temp;
    
    while(scanf("%d", &n) == 1) {
        if(n == 0) {
            return 0;
        } else {
            for(i = 0; i < n; i++) {
                scanf("%lld", &num[i]);
            }
            sort(num, num+n);
            mini = num[n-1];
            for(i = 0; i < n-1; i++)
                mini = mini * num[n-i-2] + 1;
            for(i = 0; i < n-1; i++) {
                num[i+1] = num[i] * num[i+1] + 1;
                for(j = i+1; j < n-1; j++)
                    if(num[j] > num[j+1])
                        swap(num[j], num[j+1]);    
            }
            maxi = num[n-1];
            printf("%d\n", (maxi-mini));
        }    
    }
    
    return 0;
}