using System;
using System.Linq;

namespace No389{
    public class Program{
        public static void Main(string[] args){
            var M = int.Parse(Console.ReadLine());
            var Hk = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse).Where(x => x != 0);

            var sum = Hk.Sum();
            var k = Hk.Count();

            if(k == 0){
                Console.WriteLine(1);
                return;
            }

            if(sum + k - 1 > M){
                Console.WriteLine("NA");
                return;
            }

            //TLE
            var seq = Enumerable.Range(1, M - sum + 1).ToList();
            foreach(var er in Enumerable.Range(1, M - sum - k + 1)){
                seq[seq.FindIndex(x => x % er == 0)] /= er;
            }
            foreach(var er in Enumerable.Range(1, k)) {
                seq[seq.FindIndex(x => x % er == 0)] /= er;
            }
            Console.WriteLine(seq.Aggregate(1L, (x, y) => x * y % 1000000007));
        }
    } 
}