#include <iostream>
#include <vector>
#include <cmath>
using namespace std;

int main(){
	int m;
	cin >> m;
	int k;
	int cnt = 0;
	long long int sum = 0;
	double res = 1;
	while (cin >> k) {
		if (k == 0) {
			cout << "1" << endl;
			return 0;
		}
		sum += k;
		cnt++;
	}

	m = m - sum - cnt + 1;
	if (m < 0) {
		cout << "NA" << endl;
		return 0;
	}
	else {
		for (int i = 1; i <= cnt; i++) {
			res =  (i + m)*(res/i);
		}
	}
	
	cout << (long long int)fmod(res,1000000007) << endl;

	return 0;
}