import java.util.*;

public class Main {
  public static long MOD = (long)Math.pow(10, 9) + 7;
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long m = sc.nextLong();
    ArrayList<Long> h = new ArrayList<Long>();
    long sum = 0;
    for(int i = 0; i < 1000000; i++) {
      try {
        long t = sc.nextLong();
        sum += t;
        h.add(t);
      } catch(Exception e) {
        break;
      }
    }
    long k = h.size();
    sum += (k - 1);
    long ans = 1;
    if(h.get(0) != 0) {
      if(sum > m) {
        System.out.println("NA");
      } else {
        long t = m - sum;
        long r1 = 1;
        long r2 = 1;
        for(long i = 1; i <= k; i++) {
          r1 = (r1 * (t + i)) % MOD;
          r2 = (r2 * i) % MOD;
        }
        long r3 = func(r2, MOD - 2);
        ans = (r1 * r3) % MOD;
        System.out.println(ans);
      }
    } else {
      System.out.println(1);      
    }
  }

  public static long func(long a, long x) {
    if(x == 0) return 1;
    if(x % 2 == 0) {
      long t = func(a, x / 2);
      return (t * t) % MOD;
    } else {
      long t = func(a, x / 2);
      t = (t * t) % MOD;
      return (a * t) % MOD;
    }
  }
}