#include using namespace std; #define _p(...) (void)printf(__VA_ARGS__) #define forr(x,arr) for(auto&& x:arr) #define _overload3(_1,_2,_3,name,...) name #define _rep2(i,n) _rep3(i,0,n) #define _rep3(i,a,b) for(int i=int(a);i=int(a);i--) #define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__) #define all(x) (x).begin(), (x).end() #define bit(n) (1LL<<(n)) #define sz(x) ((int)(x).size()) #define fst first #define snd second using ll=long long;using pii=pair; using vb=vector;using vs=vector; using vi=vector;using vvi=vector;using vvvi=vector; using vl=vector;using vvl=vector;using vvvl=vector; using vd=vector;using vvd=vector;using vvvd=vector; using vpii=vector;using vvpii=vector;using vvvpii=vector; templateT read(){T t;cin>>t;return t;} templateostream&operator<<(ostream&o,const pair&p){o<<'('< struct Mint { int x; Mint() : x(0) {} Mint(int y) : x(y >= 0 ? y % MOD : MOD - (-y) % MOD) {} Mint(signed long long sll) : x(sll % MOD) { if (x < 0) x += MOD; } Mint &operator+=(const Mint &rhs){ if((x += rhs.x) >= MOD) x -= MOD; return *this; } Mint &operator-=(const Mint &rhs){ if((x += MOD - rhs.x) >= MOD) x -= MOD; return *this; } Mint &operator*=(const Mint &rhs){ x = 1LL*x*rhs.x % MOD; return *this; } Mint &operator/=(const Mint &rhs){ x = (1LL*x*rhs.inv().x) % MOD; return *this; } Mint operator-() const { return Mint(-x); } Mint operator+(const Mint &rhs) const { return Mint(*this) += rhs; } Mint operator-(const Mint &rhs) const { return Mint(*this) -= rhs; } Mint operator*(const Mint &rhs) const { return Mint(*this) *= rhs; } Mint operator/(const Mint &rhs) const { return Mint(*this) /= rhs; } bool operator<(const Mint &rhs) const { return x < rhs.x; } Mint inv() const { signed a = x, b = MOD, u = 1, v = 0, t; while(b){ t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } return Mint(u); } Mint operator^(unsigned long long t) const { Mint e = *this, res = 1; for(; t; e *= e, t>>=1) if (t & 1) res *= e; return res; } }; template ostream &operator<<(ostream &os, const Mint &rhs) { return os << rhs.x; } template istream &operator>>(istream &is, Mint &rhs) { long long s; is >> s; rhs = Mint(s); return is; }; using mint = Mint; using vm=vector;using vvm=vector;using vvvm=vector; int Main() { int n = read(); int k = read(); if (k == 0) { mint ans = 1; rep(j, 2, n+1) ans *= j; return ans.x; } vector A(k); rep(i, k) A[i] = read(); sort(all(A)); mint ans = 1; int i = 0; if (A[0] == 0) i++; ll last = 0; for (; i