312Acurrencynotes.cpp

#include<iostream>
using namespace std;

int main()
{
	int n; cin >> n;	
	int a[n];
	for(int i = 0; i < n; i++)
		cin >> a[i];  
	int flag = 0;
	for(int i = 0; i < n; i++)
	{
		if(a[i] == 1)  
			flag = 1;
	}
	if(flag)
		cout <<"-1" ;
	else
		cout <<"1" ;

	return 0;
}