#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000



int main(){

	int N;
	cin>>N;
	vector<long long> A(N);
	rep(i,N){
		cin>>A[i];
		
		if(A[i]==0){
			cout<<-1<<endl;
			return 0;
		}
	}
	
	long long ans = 1LL;
	
	rep(i,N){
		if(A[i]==1)continue;
		if(A[i] >= 5){
			cout<<modulo<<endl;
			return 0;
		}
		
		long long t = 1;
		for(int j=1;j<=A[i];j++)t *= j;
		rep(j,t){
			ans *= A[i];
			if(ans > modulo){
				cout<<modulo<<endl;
				return 0;
			}
		}
	}
	
	cout<<modulo%ans<<endl;
	
	return 0;
}