#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>
const int INF = 1e8;
using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
#else
	#define DEBUG(x) true
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define rangej(a,b,c) ((a) <= (c) and (c) < (b))
#define rrangej(b,c) rangej(0,b,c)
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}

typedef pair<int,int> P;
typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<LL,LL> LP;

void ios_init(){
	//cout.setf(ios::fixed);
	//cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

const LL mod = 1e9+7;
//res.first*a+res.second*b == 1 となるresを返す (a,bは互いに素)
pair<long long, long long> extgcd(long long a,long long b)
{
	if(b==1){
		return pair<long long, long long>(0,1);
	}
	pair<long long, long long> t=extgcd(b,a%b);
	return pair<long long, long long>(t.second,t.first-a/b*t.second);
}

//modの逆元を返す
long long inverse(long long mod,long long a)
{
	return (extgcd(mod,a).second+mod)%mod;
}

//xCyを返す
long long Cinv(const long long mod, long long x, long long y){
	long long n = 1 ,r = 1;
	for(int i = 0; i < y; i++){
		n = n*(i+1)%mod;
		r = r*(x-i)%mod;
	}
	return r*inverse(mod,n)%mod;
}

int main()
{
	ios_init();
	int m;
	cin >> m;
	int sum = 0;
	std::vector<int> h;
	int in;
	while(cin >> in) if(in != 0) h.push_back(in),sum += in;
	int k = SZ(h);
	if(m-sum-k+1 < 0) cout << "NA" << endl;
	else {
		cout << Cinv(mod, m-sum+1, m-sum-k+1) << endl;
	}
	return 0;
}