#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define mem(a) memset(a,0,sizeof(a))
#define pd(a) printf("%.10f\n",a)
#define pb(a) push_back(a)
#define in(a) insert(a)
#define pi M_PI
#define R cin>>
#define F first
#define S second
#define C class
#define ll long long
#define ln cout<<'\n'
template<C T>void pr(T a){cout<<a;ln;}
template<C T,C T2>void pr(T a,T2 b){cout<<a<<' '<<b;ln;}
template<C T,C T2,C T3>void pr(T a,T2 b,T3 c){cout<<a<<' '<<b<<' '<<c;ln;}
template<C T>void PR(T a,int n){rep(i,n){if(i)cout<<' ';cout<<a[i];}ln;}
bool check(int n,int m,int x,int y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;
void extended_euclid(ll x,ll y,ll *c,ll *a,ll *b){
  ll a0,a1,a2,b0,b1,b2,r0,r1,r2,q;
  r0=x;r1=y;a0=1;a1=0;b0=0;b1=1;
  while(r1>0){
    q=r0/r1;r2=r0%r1;a2=a0-q*a1;b2=b0-q*b1;
    r0=r1;r1=r2;a0=a1;a1=a2;b0=b1;b1=b2;
  }
  *c=r0;*a=a0;*b=b0;
}
ll get_inv(ll n, ll p){
  ll a,b,c;
  extended_euclid(n,p,&c,&a,&b);
  if(a<p) a+=p;
  return a%p;
}
ll fact[2000100],fact_inv[2000100];
ll nCr(int N, int K){
  if(K<0||K>N) return 0;
  return fact[N]*fact_inv[K]%MAX*fact_inv[N-K]%MAX;
}
ll nHr(ll N, ll K){
  if(N==0 && K==0) return 1;
  if(N==0) return 0;
  return nCr(N+K-1, K);
}
void init() {
  fact[0]=1;
  REP(i,1,2000100) fact[i]=fact[i-1]*i%MAX;
  fact_inv[2000050]=get_inv(fact[2000050],MAX);
  for(int i=2000050-1;i>=0;i--) fact_inv[i]=fact_inv[i+1]*(i+1)%MAX;
}
void Main() {
  init();
  ll n,x,m=0,sum=0;
  cin >> n;
  string s;
  stringstream ss;
  getline(cin,s);
  getline(cin,s);
  ss << s;
  while(ss >> x) {
    m++;
    sum+=x;
  }
  if(sum+m-1>n) {
    pr("NA");
    return;
  } else if(sum==0) {
    pr(1);
    return;
  } else if(sum==n) {
    pr(1);
    return;
  }
  n-=sum;
  ll ans=nCr(n-1,m-2);
  if(m<=n) ans+=nCr(n-1,m-1)*2;
  if(m+1<=n) ans+=nCr(n-1,m);
  pr(ans%MAX);
}

int main() {
  ios::sync_with_stdio(0);cin.tie(0);
  Main();return 0;
}