/*  _              _     _                                             _       __      __      __   
   / \     _   _  | |_  | |__     ___    _ __   _    ___   _ __ ___   | | __  / /_    / /_    / /_  
  / _ \   | | | | | __| | '_ \   / _ \  | '__| (_)  / __| | '_ ` _ \  | |/ / | '_ \  | '_ \  | '_ \ 
 / ___ \  | |_| | | |_  | | | | | (_) | | |     _  | (__  | | | | | | |   <  | (_) | | (_) | | (_) |
/_/   \_\  \__,_|  \__| |_| |_|  \___/  |_|    (_)  \___| |_| |_| |_| |_|\_\  \___/   \___/   \___/ 
[Created Time:       2024-09-05 16:42:07]
[Last Modified Time: 2024-09-05 16:58:01] */
#pragma GCC optimize("Ofast", "unroll-loops")
#include<bits/stdc++.h>
#ifdef LOCAL
#include"debug.h"
#else
#define D(...) ((void)0)
#endif
using namespace std; using ll = long long;
#define For(i, j, k) for ( int i = (j) ; i <= (k) ; i++ )
#define Fol(i, j, k) for ( int i = (j) ; i >= (k) ; i-- )
namespace FastIO
{
// ------------------------------
// #define DISABLE_MMAP
// ------------------------------
#if ( defined(LOCAL) || defined(_WIN32) ) && !defined(DISABLE_MMAP)
#define DISABLE_MMAP
#endif
#ifdef LOCAL
	inline char gc() { return getchar(); }
	inline void pc(char c) { putchar(c); }
#else
#ifdef DISABLE_MMAP
	inline constexpr int _READ_SIZE = 1 << 18;
	inline static char _read_buffer[_READ_SIZE], *_read_ptr = nullptr, *_read_ptr_end = nullptr;
	inline char gc()
	{
		if ( __builtin_expect(_read_ptr == _read_ptr_end, false) )
		{
			_read_ptr = _read_buffer, _read_ptr_end = _read_buffer + fread(_read_buffer, 1, _READ_SIZE, stdin);
			if ( __builtin_expect(_read_ptr == _read_ptr_end, false) ) return EOF;
		}
		return *_read_ptr++;
	}
#else
#include<sys/mman.h>
	inline static const char *_read_ptr = (const char *)mmap(nullptr, 0x7fffffff, 1, 2, 0, 0);
	inline char gc() { return *_read_ptr++; }
#endif
	inline constexpr int _WRITE_SIZE = 1 << 18;
	inline static char _write_buffer[_WRITE_SIZE], *_write_ptr = _write_buffer;
	inline void pc(char c)
	{
		*_write_ptr++ = c;
		if ( __builtin_expect(_write_buffer + _WRITE_SIZE == _write_ptr, false) )
			fwrite(_write_buffer, 1, _write_ptr - _write_buffer, stdout), _write_ptr = _write_buffer;
	}
	inline struct _auto_flush
	{
		inline ~_auto_flush() { fwrite(_write_buffer, 1, _write_ptr - _write_buffer, stdout); }
	}	_auto_flush;
#endif
#define println println_ // don't use C++23 std::println
	template < class T > inline constexpr bool _is_signed = numeric_limits < T >::is_signed;
	template < class T > inline constexpr bool _is_unsigned = numeric_limits < T >::is_integer && !_is_signed < T >;
#if __SIZEOF_LONG__ == 64
	template <> inline constexpr bool _is_signed < __int128 > = true;
	template <> inline constexpr bool _is_unsigned < __uint128_t > = true;
#endif
	inline void read(char &c) { do c = gc(); while ( !isgraph(c) ); }
	inline void read_cstr(char *s)
	{
		char c = gc(); while ( !isgraph(c) ) c = gc();
		while ( isgraph(c) ) *s++ = c, c = gc(); *s = 0;
	}
	inline void read(string &s)
	{
		char c = gc(); s.clear(); while ( !isgraph(c) ) c = gc();
		while ( isgraph(c) ) s.push_back(c), c = gc();
	}
	template < class T, enable_if_t < _is_signed < T >, int > = 0 >
	inline void read(T &x)
	{
		char c = gc(); bool f = true; x = 0;
		while ( !isdigit(c) ) { if ( c == 45 ) f = false; c = gc(); }
		if ( f ) while ( isdigit(c) ) x = x * 10 + ( c & 15 ), c = gc();
		else     while ( isdigit(c) ) x = x * 10 - ( c & 15 ), c = gc();
	}
	template < class T, enable_if_t < _is_unsigned < T >, int > = 0 >
	inline void read(T &x)
	{
		char c = gc(); while ( !isdigit(c) ) c = gc();
		x = 0; while ( isdigit(c) ) x = x * 10 + ( c & 15 ), c = gc();
	}
	inline void write(char c) { pc(c); }
	inline void write_cstr(const char *s) { while ( *s ) pc(*s++); }
	inline void write(const string &s) { for ( char c : s ) pc(c); }
	template < class T, enable_if_t < _is_signed < T >, int > = 0 >
	inline void write(T x)
	{
		char buffer[numeric_limits < T >::digits10 + 1]; int digits = 0;
		if ( x >= 0 )  do buffer[digits++] =  ( x % 10 ) | 48, x /= 10; while ( x );
		else { pc(45); do buffer[digits++] = -( x % 10 ) | 48, x /= 10; while ( x ); }
		while ( digits ) pc(buffer[--digits]);
	}
	template < class T, enable_if_t < _is_unsigned < T >, int > = 0 >
	inline void write(T x)
	{
		char buffer[numeric_limits < T >::digits10]; int digits = 0;
		do buffer[digits++] = ( x % 10 ) | 48, x /= 10; while ( x );
		while ( digits ) pc(buffer[--digits]);
	}
	template < int N > struct _tuple_io_helper
	{
		template < class ...T > static inline void _read(tuple < T... > &x) { _tuple_io_helper < N - 1 >::_read(x), read(get<N - 1>(x)); }
		template < class ...T > static inline void _write(const tuple < T... > &x) { _tuple_io_helper < N - 1 >::_write(x), pc(32), write(get<N - 1>(x)); }
	};
	template <> struct _tuple_io_helper < 1 >
	{
		template < class ...T > static inline void _read(tuple < T... > &x) { read(get<0>(x)); }
		template < class ...T > static inline void _write(const tuple < T... > &x) { write(get<0>(x)); }
	};
	template < class ...T > inline void read(tuple < T... > &x) { _tuple_io_helper < sizeof...(T) >::_read(x); }
	template < class ...T > inline void write(const tuple < T... > &x) { _tuple_io_helper < sizeof...(T) >::_write(x); }
	template < class T1, class T2 > inline void read(pair < T1, T2 > &x) { read(x.first), read(x.second); }
	template < class T1, class T2 > inline void write(const pair < T1, T2 > &x) { write(x.first), pc(32), write(x.second); }
	template < class T1, class ...T2 > inline void read(T1 &x, T2 &...y) { read(x), read(y...); }
	template < class ...T > inline void read_cstr(char *x, T *...y) { read_cstr(x), read_cstr(y...); }
	template < class T1, class ...T2 > inline void write(const T1 &x, const T2 &...y) { write(x), write(y...); }
	template < class ...T > inline void write_cstr(const char *x, const T *...y) { write_cstr(x), write_cstr(y...); }
	template < class T > inline void print(const T &x) { write(x); }
	inline void print_cstr(const char *x) { write_cstr(x); }
	template < class T1, class ...T2 > inline void print(const T1 &x, const T2 &...y) { write(x), pc(32), print(y...); }
	template < class ...T > inline void print_cstr(const char *x, const T *...y) { write_cstr(x), pc(32), print_cstr(y...); }
	inline void println() { pc(10); } inline void println_cstr() { pc(10); }
	template < class ...T > inline void println(const T &...x) { print(x...), pc(10); }
	template < class ...T > inline void println_cstr(const T *...x) { print_cstr(x...), pc(10); }
}	using FastIO::read, FastIO::read_cstr, FastIO::write, FastIO::write_cstr, FastIO::println, FastIO::println_cstr;
template < int P_ > class Modint
{
	using MI = Modint;
	inline Modint(int x, int) : v(x) {}
	inline static int add(int x) { return x < P ? x : x - P; }
	inline static int sub(int x) { return x >= 0 ? x : x + P; }
public:
	static constexpr int P = P_; int v;
	inline Modint() : v(0) {}
	inline Modint(const MI &x) : v(x.v) {}
	template < class T, enable_if_t < numeric_limits < T >::is_integer, int > = 0 >
	inline Modint(T x) : v(sub(x % P)) {}
	template < class T, enable_if_t < numeric_limits < T >::is_integer, int > = 0 >
	explicit inline operator T()const { return v; }
	inline friend bool operator==(const MI &x, const MI &y) { return x.v == y.v; }
	inline friend bool operator!=(const MI &x, const MI &y) { return x.v != y.v; }
	inline MI &operator=(const MI &x) & { v = x.v; return *this; }
	inline MI &operator++() & { v < P - 1 ? v++ : v = 0; return *this; }
	inline MI operator++(int) & { MI x = *this; v < P - 1 ? v++ : v = 0; return x; }
	inline MI &operator--() & { v ? v-- : v = P - 1; return *this; }
	inline MI operator--(int) & { MI x = *this; v ? v-- : v = P - 1; return x; }
	inline MI operator-()const { return MI(v ? P - v : 0, 0); }
	inline friend MI operator+(const MI &x, const MI &y) { return MI(add(x.v + y.v), 0); }
	inline friend MI operator-(const MI &x, const MI &y) { return MI(sub(x.v - y.v), 0); }
	inline friend MI operator*(const MI &x, const MI &y) { return MI((ll)x.v * y.v % P, 0); }
	inline friend MI operator/(const MI &x, const MI &y) { return x * y.inv(); }
	inline MI &operator+=(const MI &x) & { v = add(v + x.v); return *this; }
	inline MI &operator-=(const MI &x) & { v = sub(v - x.v); return *this; }
	inline MI &operator*=(const MI &x) & { v = (ll)v * x.v % P; return *this; }
	inline MI &operator/=(const MI &x) & { return *this *= x.inv(); }
	template < class T, enable_if_t < numeric_limits < T >::is_integer, int > = 0 >
	inline MI qpow(T y)const
	{ MI x(*this), z(1, 0); while ( y ) { if ( y & 1 ) z *= x; if ( y >>= 1 ) x *= x; } return z; }
	template < class T, enable_if_t < numeric_limits < T >::is_integer, int > = 0 >
	inline friend MI qpow(const MI &x, T y) { return x.qpow(y); }
	inline MI inv()const { assert(v); return qpow(P - 2); }
	inline friend MI inv(const MI &x) { return x.inv(); }
	inline friend istream &operator>>(istream &is, MI &x) { return is >> x.v; }
	inline friend ostream &operator<<(ostream &os, const MI &x) { return os << x.v; }
};	using MI = Modint < 1000000007 >;
struct binom
{
	MI fac[100009], ifac[100009];
	inline binom()
	{
		constexpr int n = sizeof(fac) / sizeof(*fac) - 1;
		fac[0] = 1; For(i, 1, n) fac[i] = i * fac[i - 1];
		ifac[n] = inv(fac[n]); Fol(i, n, 1) ifac[i - 1] = i * ifac[i];
	}
}	binom;
inline MI fac(int x) { return x >= 0 ? binom.fac[x] : 0; }
inline MI ifac(int x) { return x >= 0 ? binom.ifac[x] : 0; }
inline MI c(int x, int y) { return x >= y && y >= 0 ? fac(x) * ifac(y) * ifac(x - y) : 0; }
mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());
template < class T > inline T R(T l, T r) { return uniform_int_distribution < T >(l, r)(rnd); }
using ull = unsigned long long; using A = array < int, 51 >; const ull B = R(233333ull, -233333ull);
struct H { inline ull operator()(const A &x)const { ull z = 0; For(i, 1, 50) z = z * B + x[i]; return z; } };
int n, a[100009]; A cnt; unordered_map < A, MI, H > mem; MI ans;
inline MI dfs(int s, const A &c)
{
	int mx = 0; Fol(i, 50, 1) if ( c[i] ) { mx = i; break; }
	if ( s >= mx ) { int cc = 0; For(i, 1, mx) cc += c[i]; return fac(cc); }
	if ( mem.count(c) ) return mem[c];
	MI z = 0; For(i, 1, s) if ( c[i] ) { A cc = c; cc[i]--, z += c[i] * dfs(s + i, cc); } return mem[c] = z;
}
int main()
{
	read(n);
	For(i, 0, n) read(a[i]);
	For(i, 1, n) cnt[a[i]]++;
	ans = dfs(*a, cnt);
	For(i, 1, cnt[0]) ans *= n - cnt[0] + i;
	return println(ans.v), 0;
}
// 想上GM捏 想上GM捏 想上GM捏 想上GM捏 想上GM捏
// 伊娜可爱捏 伊娜贴贴捏