CodeForces 560A Currency System in Geraldion

A. Currency System in Geraldion

time limit per test
2 seconds

memory limit per test
256 megabytes

input
standard input

output
standard output

A magic island Geraldion, where Gerald lives, has its own currency system. It uses banknotes of several values. But the problem is, the system is not perfect and sometimes it happens that Geraldionians cannot express a certain sum of money with any set of banknotes.
Of course, they can use any number of banknotes of each value. Such sum is called unfortunate. Gerald wondered: what is the minimumunfortunate sum?

Input

The first line contains number n (1 ≤ n ≤ 1000)
— the number of values of the banknotes that used in Geraldion.

The second line contains n distinct space-separated numbers a1, a2, ..., an (1 ≤ ai ≤ 106)
— the values of the banknotes.

Output

Print a single line — the minimum unfortunate sum. If there are no unfortunate sums, print  - 1.

Examples

input

5
1 2 3 4 5

output

-1

题意：魔法岛Geraldion,杰拉尔德的生活,有自己的货币系统。它使用纸币的几个值。但问题是,系统并不完美,有时碰巧Geraldionians不能表达一定数额的资金与任何的钞票。当然,他们可以使用任意数量的每个值的钞票。这样的总和称为不幸的。杰拉尔德在想:最低不幸的总和是多少?
思路： 只有两种结果，如果最小的货币价值不是1，那么不能组成的最小数字就是1，如果最小货币价值是1，那么就不存在

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int a[1100];
int main()
{
int n,m,i,j;
while(scanf("%d",&n)!=EOF)
{
for(i=0;i<n;i++)
scanf("%d",&a[i]);
sort(a,a+n);
if(a[0]==1)
{
printf("-1\n");
}
else if(a[0]!=1)
{
printf("1\n");
}
}
return 0;
}