#line 2 "/home/defineprogram/Desktop/Library/template/template.cpp" #include using namespace std; #define ll long long #define rep(i, n) for (int i = 0; i < n; i++) #define REP(i, n) for (int i = 1; i < n; i++) #define rev(i, n) for (int i = n - 1; i >= 0; i--) #define REV(i, n) for (int i = n - 1; i > 0; i--) #define all(v) v.begin(), v.end() #define PL pair #define PI pair #define len(s) (int)s.size() template inline bool chmin(T &a, U b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T &a, U b) { if (a < b) { a = b; return true; } return false; } constexpr ll inf = 3e18; #line 3 "/home/defineprogram/Desktop/Library/math/extgcd.cpp" ll extGCD(ll a, ll b, ll &x, ll &y) { if (!b) { x = 1; y = 0; return a; } ll d = extGCD(b, a % b, y, x); y -= a / b * x; return d; } ll modinv(ll a, ll m) { ll x, y; extGCD(a, m, x, y); return (x % m + m) % m; } #line 4 "/home/defineprogram/Desktop/Library/math/modint.cpp" template struct mint { int32_t n; mint() : n(0) {} mint(ll x) : n(x >= 0 ? x % MOD : (MOD - (-x) % MOD) % MOD) {} mint &operator+=(const mint &p) { if ((n += p.n) >= MOD) n -= MOD; return *this; } mint &operator-=(const mint &p) { if ((n += MOD - p.n) >= MOD) n -= MOD; return *this; } mint &operator*=(const mint &p) { n = 1ll * n * p.n % MOD; return *this; } mint &operator/=(const mint &p) { *this *= p.inverse(); return *this; } mint operator-() const { return mint(-n); } mint operator+(const mint &p) const { return mint(*this) += p; } mint operator-(const mint &p) const { return mint(*this) -= p; } mint operator*(const mint &p) const { return mint(*this) *= p; } mint operator/(const mint &p) const { return mint(*this) /= p; } bool operator==(const mint &p) const { return n == p.n; } bool operator!=(const mint &p) const { return n != p.n; } friend ostream &operator<<(ostream &os, const mint &p) { return os << p.n; } friend istream &operator>>(istream &is, mint &p) { int x; is >> x; p = mint(x); return is; } mint pow(int64_t x) const { mint res(1), mul(n); while (x > 0) { if (x & 1) res *= mul; mul *= mul; x >>= 1; } return res; } mint inverse() const { return mint(modinv(n,MOD)); } }; /* @brief mod int @docs docs/modint.md */ #line 3 "main.cpp" constexpr int mod=998244353; using modint=mint; #line 3 "/home/defineprogram/Desktop/Library/math/Combination.cpp" template struct Combination { using modint = mint; vector perm, inv; Combination(int x = 1e6) { perm.resize(x); inv.resize(x); perm[0] = modint(1); REP(i, x + 1) perm[i] = perm[i - 1] * i; inv[x] = perm[x].pow(MOD - 2); for (int i = x - 1; i >= 0; i--) { inv[i] = inv[i + 1] * (i + 1); } } modint nCk(int x, int y) { if (x < y) return modint(0); return perm[x] * inv[x - y] * inv[y]; } }; /* @brief Combination (nCk) @docs docs/Combination.md */ #line 7 "main.cpp" Combination C; int N,M; int P[5005]; bool used[5005]; int main() { cin.tie(0); ios::sync_with_stdio(false); cin>>N>>M; rep(i,N){ cin>>P[i];P[i]--; } modint ans=0; for(int i=2;i<=M;i++){ modint tapi=1; memset(used,false,sizeof(used)); rep(j,N)if(!used[j]){ int cur=j; int cnt=0; do{ used[cur]=true; cnt++; cur=P[cur]; }while(cur!=j); modint dp[2],dp2[2]; dp[0]=i; rep(k,cnt-2){ swap(dp,dp2); dp[0]=dp[1]=0; dp[0]+=dp2[1]; dp[1]+=dp2[0]*(i-1); dp[1]+=dp2[1]*(i-2); } modint res=dp[0]*(i-1)+dp[1]*(i-2); tapi*=res; } if((M-i)%2==0)ans+=C.nCk(M,i)*tapi; else ans-=C.nCk(M,i)*tapi; } REP(i,M+1)ans/=i; cout<