#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if(x < y) x = y; }


template<int MOD>
struct ModInt {
	static const int Mod = MOD;
	unsigned x;
	ModInt() : x(0) {}
	ModInt(signed sig) { int sigt = sig % MOD; if(sigt < 0) sigt += MOD; x = sigt; }
	ModInt(signed long long sig) { int sigt = sig % MOD; if(sigt < 0) sigt += MOD; x = sigt; }
	int get() const { return (int)x; }

	ModInt &operator+=(ModInt that) { if((x += that.x) >= MOD) x -= MOD; return *this; }
	ModInt &operator-=(ModInt that) { if((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
	ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
	ModInt &operator/=(ModInt that) { return *this *= that.inverse(); }

	ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
	ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
	ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
	ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }

	ModInt inverse() const {
		signed a = x, b = MOD, u = 1, v = 0;
		while(b) {
			signed t = a / b;
			a -= t * b; std::swap(a, b);
			u -= t * v; std::swap(u, v);
		}
		if(u < 0) u += Mod;
		ModInt res; res.x = (unsigned)u;
		return res;
	}
};
typedef ModInt<1000000007> mint;

vector<mint> fact, factinv;
void nCr_computeFactinv(int N) {
	N = min(N, mint::Mod - 1);
	fact.resize(N + 1); factinv.resize(N + 1);
	fact[0] = 1;
	rer(i, 1, N) fact[i] = fact[i - 1] * i;
	factinv[N] = fact[N].inverse();
	for(int i = N; i >= 1; i --) factinv[i - 1] = factinv[i] * i;
}
mint nCr(int n, int r) {
	if(n >= mint::Mod)
		return nCr(n % mint::Mod, r % mint::Mod) * nCr(n / mint::Mod, r / mint::Mod);
	return r > n ? 0 : fact[n] * factinv[n - r] * factinv[r];
}

class FastInput {
	bool _end;
public:
	FastInput() : _end(false) {}

	operator void*() { return _end ? 0 : (void*)this; }

	template<typename T>
	void read_unsigned(T *res) {
		T x = 0;
		for(char c = skip(); '0' <= c && c <= '9'; c = gc())
			x = x * 10 + (c - '0');
		*res = x;
	}

	template<typename T>
	void read_signed(T *res) {
		char c = skip();
		bool sign = false;
		if(c == '-') sign = true, c = gc();
		T x = 0;
		for(; '0' <= c && c <= '9'; c = gc())
			x = x * 10 + (c - '0');
		*res = !sign ? x : -x;
	}

	void read_c_string(char *str, int *len) {
		int n = 0;
		for(char c = skip(); !is_delim(c); c = gc())
			str[n ++] = c;
		str[n] = 0;
		*len = n;
	}

	void read_string(std::string *str) {
		str->clear();
		for(char c = skip(); !is_delim(c); c = gc())
			*str += c;
	}

	void read_line(std::string *str) {
		str->clear();
		for(char c = gc(); c != '\n'; c = gc())
			*str += c;
		if(!str->empty() && (*str)[str->size() - 1] == '\r') str->resize(str->size() - 1);
	}

	void read_double(double *res) {
		std::string buf;
		read_string(&buf);
		sscanf(buf.c_str(), "%lf", res);
	}

	void read_char(char *res) {
		*res = skip();
	}

	void read_string_buf(char *res, int n) {
		*res = skip();
	}

	FastInput &operator()(char &res) { read_char(&res); return *this; }
	FastInput &operator()(int &res) { read_signed(&res); return *this; }
	FastInput &operator()(unsigned &res) { read_unsigned(&res); return *this; }
	FastInput &operator()(long long &res) { read_signed(&res); return *this; }
	FastInput &operator()(unsigned long long &res) { read_unsigned(&res); return *this; }
	FastInput &operator()(char *res) { int len; read_c_string(res, &len); return *this; }
	FastInput &operator()(std::string &res) { read_string(&res); return *this; }
	FastInput &operator()(double &res) { read_double(&res); return *this; }

	template<typename T1, typename T2>
	FastInput &operator()(T1 &res1, T2 &res2) {
		return operator()(res1)(res2);
	}
	template<typename T1, typename T2, typename T3>
	FastInput &operator()(T1 &res1, T2 &res2, T3 &res3) {
		return operator()(res1)(res2)(res3);
	}

	template<typename T>
	FastInput &a(T *a, int n) {
		for(int i = 0; i < n; ++ i)
			operator()(a[i]);
		return *this;
	}

	template<typename T>
	FastInput &operator()(vector<T> &v) {
		for(size_t i = 0; i < v.size(); ++ i)
			operator()(v[i]);
		return *this;
	}

private:
	static char gc() {
#if defined(__GNUC__) && !defined(__MINGW32__)
		return (char)getchar_unlocked();
#elif defined(_MSC_VER)
		return (char)_getchar_nolock();
#else
		return (char)getchar();
#endif
	}

	static bool is_delim(char c) {
		return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == EOF;
	}

	char skip() {
		if(_end) return EOF;
		char c;
		for(c = gc(); c != -1 && is_delim(c); c = gc());
		if(c == EOF) _end = true;
		return c;
	}
} in;

int main() {
	int N;
	in(N);
	vector<int> H;
	{
		int h;
		while(in(h))
			H.push_back(h);
	}
	int sum = accumulate(H.begin(), H.end(), 0);
	if(sum == 0) {
		puts("1");
	} else if(sum + (int)H.size() - 1 > N) {
		puts("NA");
	} else {
		nCr_computeFactinv(N);
		mint ans = nCr(N - sum + 1, H.size());
		printf("%d\n", ans.get());
	}
	return 0;
}