#include <iostream>
#include <math.h>
#include <string>
#include <algorithm>
using namespace std;

int kaijo(long a){
	long n=1;
	if (a > 0){
		for (long i = a; i > 0; i--){
			n *= i;
			n = n % 1000000007;
		}
	}
	else{
		n = 1;
	}
	return n;
}

int permtation(long a,long b){
	long n = 1;
	if (b != 0){
		for (long i = 0; i < b; i++){
			n *= (a-i);
			n = n % 1000000007;
		}
	}
	else{
		n = 1;
	}
	return n;
}

int main(){
	long m;
	long a = 0;
	string s;
	string s1;
	long h;
	long cnt = 0;
	long ans;
	long p, k;
	cin >> m;
	cin.ignore();
	getline(cin, s);
	while (1){
		s1 = s;
		//cout << s1 << endl;
		a = s1.find(" ", 0);
		if (a == -1){
			h = stoi(s1);
			m -= h;
			cnt++;
			break;
		}
		else{
			s1.erase(a,s1.length());
			h = stoi(s1);
			m -= h;
			cnt++;
			s.erase(0, a + 1);
			//cout << s << endl;
		}
	}
	long judge = m - cnt + 1;
	//cout << m << endl;
	//cout << cnt << endl;
	//cout << judge << endl;
	
	if (judge <0){
		cout << "NA" << endl;
	}
	else{
		if (judge>cnt){
			p = permtation(m + 1, cnt);
			k = kaijo(cnt);
			
			while (1){
				ans = p / k;
				if (ans*k == p){
					cout << ans << endl;
					break;
				}
				else{
					p += 1000000007;
				}
			}
		}
		else{
			p = permtation(m + 1, judge);
			k = kaijo(judge);
			
			while (1){
				ans = p / k;
				if (ans*k == p){
					cout << ans << endl;
					break;
				}
				else{
					p += 1000000007;
				}
			}
		}
		//ans = kaijo(m + 1) / (kaijo(m - cnt + 1)*kaijo(cnt));
		//cout << ans << endl;
		//cout << m << endl;
	}
	return 0;
}