Codeforces Round #313 A. Currency System in Geraldion(簡單題)

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.

Sample test(s) input

5
1 2 3 4 5

output

-1

題意：問n個數所不能組成的最小的正整數是多少，如果都能組成輸出-1

#include
#include

using namespace std;

int main()
{
    int n;
    int m;
    while(scanf("%d",&n)!=EOF)
    {
        int flag = 0;
        for(int i=0;i
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