CodeForces 560A Currency System in Geraldion 【水題】

Description

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, ..., a_n (1 ≤ a_i ≤ 10⁶) — the values of the banknotes.

Output

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

Sample Input

Input

5
1 2 3 4 5

Output

-1

/*
    CodeForces 560A	Currency System in Geraldion
    題意：給定n種貨幣的面值,每種貨幣可以使用的數量沒有限制,問你
          最小的不能表示的金額是多少,如果不存在輸出-1
    類型：水題
    分析：只要看有沒有1就行了,如果有1能表示所有金額;
          如果沒有,1沒辦法用其他金額表示
*/
#include<cstdio>
#include<iostream>
#include<vector>
using namespace std;
int main()
{
    int n;cin>>n;
    int flag=0,a;
    for(int i=0;i<n;i++){
        scanf("%d",&a);
        if(a==1)flag=1;
    }
    if(flag)puts("-1");
    else puts("1");
    return 0;
}