Problem: Cirno has prepared n arrays of length n each. Each array is a permutation of n integers from 1 to n. These arrays are special: for all 1 ≤ i ≤ n, if we take the i-th element of each array and form another array of length n with these elements, the resultant array is also a permutation of n integers from 1 to n. In the other words, if you put these n arrays under each other to form a matrix with n rows and n columns, this matrix is a [Latin square](https://en.wikipedia.org/wiki/Latin_square).

Afterwards, Cirno added additional n arrays, each array is a permutation of n integers from 1 to n. For all 1 ≤ i ≤ n, there exists at least one position 1 ≤ k ≤ n, such that for the i-th array and the (n + i)-th array, the k-th element of both arrays is the same. Notice that the arrays indexed from n + 1 to 2n don't have to form a Latin square. 

Also, Cirno made sure that for all 2n arrays, no two arrays are completely equal, i. e. for all pair of indices 1 ≤ i < j ≤ 2n, there exists at least one position 1 ≤ k ≤ n, such that the k-th elements of the i-th and j-th array are different.

Finally, Cirno arbitrarily changed the order of 2n arrays.

AquaMoon calls a subset of all 2n arrays of size n good if these arrays from a Latin square.

AquaMoon wants to know how many good subsets exist. Because this number may be particularly large, find it modulo 998 244 353. Also, she wants to find any good subset. Can you help her?

Input

The input consists of multiple test cases. The first line contains a single integer t (1 ≤ t ≤ 100) — the number of test cases.

The first line of each test case contains a single integer n (5 ≤ n ≤ 500).

Then 2n lines followed. The i-th of these lines contains n integers, representing the i-th array.

It is guaranteed, that the sum of n over all test cases does not exceed 500.

Output

For each test case print two lines.

In the first line, print the number of good subsets by modulo 998 244 353.

In the second line, print n indices from 1 to 2n — indices of the n arrays that form a good subset (you can print them in any order). If there are several possible answers — print any of them.

Example

Input


3
7
1 2 3 4 5 6 7
2 3 4 5 6 7 1
3 4 5 6 7 1 2
4 5 6 7 1 2 3
5 6 7 1 2 3 4
6 7 1 2 3 4 5
7 1 2 3 4 5 6
1 2 3 4 5 7 6
1 3 4 5 6 7 2
1 4 5 6 7 3 2
1 5 6 7 4 2 3
1 6 7 5 2 3 4
1 7 6 2 3 4 5
1 7 2 3 4 5 6
5
4 5 1 2 3
3 5 2 4 1
1 2 3 4 5
5 2 4 1 3
3 4 5 1 2
2 3 4 5 1
1 3 5 2 4
4 1 3 5 2
2 4 1 3 5
5 1 2 3 4
6
2 3 4 5 6 1
3 1 2 6 4 5
6 1 2 3 4 5
5 6 1 3 2 4
4 3 6 5 2 1
5 6 1 2 3 4
4 5 6 1 2 3
3 4 5 6 1 2
1 2 3 4 5 6
2 5 4 1 6 3
3 2 5 4 1 6
1 4 3 6 5 2


Output


1
1 2 3 4 5 6 7
2
1 3 5 6 10
4
1 3 6 7 8 9

Note

In the first test case, the number of good subsets is 1. The only such subset is the set of arrays with indices 1, 2, 3, 4, 5, 6, 7.

In the second test case, the number of good subsets is 2. They are 1, 3, 5, 6, 10 or 2, 4, 7, 8, 9.

Solution (in CPP):

Solution:
#pragma comment(linker, "/stack:1000000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")

#define _CRT_SECURE_NO_WARNINGS
# include <iostream>
# include <cmath>
# include <algorithm>
# include <stdio.h>
# include <cstdint>
# include <cstring>
# include <string>
# include <cstdlib>
# include <vector>
# include <bitset>
# include <map>
# include <queue>
# include <ctime>
# include <stack>
# include <set>
# include <list>
# include <random>
# include <deque>
# include <functional>
# include <iomanip>
# include <sstream>
# include <fstream>
# include <complex>
# include <numeric>
//# include <immintrin.h>
# include <cassert>
# include <array>
# include <tuple>
# include <unordered_map>
# include <unordered_set>
# include <chrono>

using namespace std;

#define VA_NUM_ARGS(...) VA_NUM_ARGS_IMPL_((0,__VA_ARGS__, 6,5,4,3,2,1))
#define VA_NUM_ARGS_IMPL_(tuple) VA_NUM_ARGS_IMPL tuple
#define VA_NUM_ARGS_IMPL(_0,_1,_2,_3,_4,_5,_6,N,...) N
#define macro_dispatcher(macro, ...) macro_dispatcher_(macro, VA_NUM_ARGS(__VA_ARGS__))
#define macro_dispatcher_(macro, nargs) macro_dispatcher__(macro, nargs)
#define macro_dispatcher__(macro, nargs) macro_dispatcher___(macro, nargs)
#define macro_dispatcher___(macro, nargs) macro ## nargs
#define DBN1(a)           cerr<<#a<<"="<<(a)<<"\n"
#define DBN2(a,b)         cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<"\n"
#define DBN3(a,b,c)       cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<"\n"
#define DBN4(a,b,c,d)     cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<"\n"
#define DBN5(a,b,c,d,e)   cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<", "<<#e<<"="<<(e)<<"\n"
#define DBN6(a,b,c,d,e,f) cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<", "<<#e<<"="<<(e)<<", "<<#f<<"="<<(f)<<"\n"
#define DBN(...) macro_dispatcher(DBN, __VA_ARGS__)(__VA_ARGS__)
#define DA(a,n) cerr<<#a<<"=["; printarray(a,n); cerr<<"]\n"
#define DAR(a,n,s) cerr<<#a<<"["<<s<<"-"<<n-1<<"]=["; printarray(a,n,s); cerr<<"]\n"

#ifdef _MSC_VER
#define PREFETCH(ptr, rw, level) ((void)0)
#else
#define PREFETCH(ptr, rw, level) __builtin_prefetch(ptr, rw, level)
#endif

#if defined _MSC_VER
#define ASSUME(condition) ((void)0)
#define __restrict
#else
#define ASSUME(condition) ((condition) ? true : (__builtin_unreachable(), false))
#endif

#ifdef LOCAL
#define CURTIME() cerr << clock() * 1.0 / CLOCKS_PER_SEC << endl
#else
#define CURTIME()
#endif

typedef long long ll;
typedef long double ld;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef int itn;

template<class T1, class T2, class T3>
struct triple{ T1 a; T2 b; T3 c; triple() : a(T1()), b(T2()), c(T3()) {}; triple(T1 _a, T2 _b, T3 _c) :a(_a), b(_b), c(_c){} };
template<class T1, class T2, class T3>
bool operator<(const triple<T1,T2,T3>&t1,const triple<T1,T2,T3>&t2){if(t1.a!=t2.a)return t1.a<t2.a;else if(t1.b!=t2.b)return t1.b<t2.b;else return t1.c<t2.c;}
template<class T1, class T2, class T3>
bool operator>(const triple<T1,T2,T3>&t1,const triple<T1,T2,T3>&t2){if(t1.a!=t2.a)return t1.a>t2.a;else if(t1.b!=t2.b)return t1.b>t2.b;else return t1.c>t2.c;}
#define tri triple<int,int,int>
#define trll triple<ll,ll,ll>

#define FI(n) for(int i=0;i<(n);++i)
#define FJ(n) for(int j=0;j<(n);++j)
#define FK(n) for(int k=0;k<(n);++k)
#define FL(n) for(int l=0;l<(n);++l)
#define FQ(n) for(int q=0;q<(n);++q)
#define FOR(i,a,b) for(int i = (a), __e = (int) (b); i < __e; ++i)
#define all(a) std::begin(a), std::end(a)
#define reunique(v) v.resize(std::unique(v.begin(), v.end()) - v.begin())

#define sqr(x) ((x) * (x))
#define sqrt(x) sqrt(1.0 * (x))
#define pow(x, n) pow(1.0 * (x), n)

#define COMPARE(obj) [&](const std::decay_t<decltype(obj)>& a, const std::decay_t<decltype(obj)>& b)
#define COMPARE_BY(obj, field) [&](const std::decay_t<decltype(obj)>& a, const std::decay_t<decltype(obj)>& b) { return a.field < b.field; }

//long double cpu_time() {
//#if defined(_WIN32) || defined(_WIN64)
//    FILETIME creation_ft, exit_ft, kernel_ft, user_ft;
//    GetProcessTimes(GetCurrentProcess(), &creation_ft, &exit_ft, &kernel_ft, &user_ft);
//    auto extract_time = [](const FILETIME& ft) {
//        return 1e-7L * (ft.dwLowDateTime | uint64_t(ft.dwHighDateTime) << 32);
//    };
//    return extract_time(user_ft) + extract_time(kernel_ft);
//#else
//    return (long double) clock() / CLOCKS_PER_SEC;
//#endif
//}
#define checkbit(n, b) (((n) >> (b)) & 1)
#define setbit(n, b) ((n) | (static_cast<std::decay<decltype(n)>::type>(1) << (b)))
#define removebit(n, b) ((n) & ~(static_cast<std::decay<decltype(n)>::type>(1) << (b)))
#define flipbit(n, b) ((n) ^ (static_cast<std::decay<decltype(n)>::type>(1) << (b)))
inline int countBits(uint v){v=v-((v>>1)&0x55555555);v=(v&0x33333333)+((v>>2)&0x33333333);return(((v+(v>>4))&0xF0F0F0F)*0x1010101)>>24;}
inline int countBits(ull v){uint t=v>>32;uint p=(v & ((1ULL << 32) - 1)); return countBits(t) + countBits(p); }
inline int countBits(ll v){return countBits((ull)v); }
inline int countBits(int v){return countBits((uint)v); }
unsigned int reverseBits(uint x){ x = (((x & 0xaaaaaaaa) >> 1) | ((x & 0x55555555) << 1)); x = (((x & 0xcccccccc) >> 2) | ((x & 0x33333333) << 2)); x = (((x & 0xf0f0f0f0) >> 4) | ((x & 0x0f0f0f0f) << 4)); x = (((x & 0xff00ff00) >> 8) | ((x & 0x00ff00ff) << 8)); return((x >> 16) | (x << 16)); }
template<class T> inline int sign(T x){ return x > 0 ? 1 : x < 0 ? -1 : 0; }
inline bool isPowerOfTwo(int x){ return (x != 0 && (x&(x - 1)) == 0); }
constexpr ll power(ll x, int p) { return p == 0 ? 1 : (x * power(x, p - 1)); }
template<class T>
inline bool inRange(const T& val, const T& min, const T& max) { return min <= val && val <= max; }
//template<class T1, class T2, class T3> T1 inline clamp(T1 x, const T2& a, const T3& b) { if (x < a) return a; else if (x > b) return b; else return x; }
//unsigned long long rdtsc() { unsigned long long ret = 0;
//#ifdef __clang__
//    return __builtin_readcyclecounter();
//#endif
//#ifndef _MSC_VER
//    asm volatile("rdtsc" : "=A" (ret) : :);
//#endif
//    return ret; }
// Fast IO ********************************************************************************************************
const int __BS = 4096;
static char __bur[__BS + 16], *__er = __bur + __BS, *__ir = __er;
auto c = []() { if (__ir == __er) {std::fill(__bur, __bur + __BS, 0); cin.read(__bur, __BS); __ir = __bur; };};
template<class T = int> T readInt() {
    c(); while (*__ir && (*__ir < '0' || *__ir > '9') && *__ir != '-') ++__ir; c();
    bool m = false; if (*__ir == '-') {++__ir; c(); m = true;}
    T r = 0; while (*__ir >= '0' && *__ir <= '9') {r = r * 10 + *__ir - '0', ++__ir; c();}
    ++__ir; return m ? -r : r;
}
string readString() {
    string r; c(); while (*__ir && isspace(*__ir)) {++__ir; c();}
    while (!isspace(*__ir)) {r.push_back(*__ir); ++__ir; c();}
    ++__ir; return r;
}
char readChar() {
    c(); while (*__ir && isspace(*__ir)) {++__ir; c();} return *__ir++;
}
static char __buw[__BS + 20], *__iw = __buw, *__ew = __buw + __BS;
template<class T>
void writeInt(T x, char endc = '\n') {
    if (x < 0) *__iw++ = '-', x = -x; if (x == 0) *__iw++ = '0';
    char* s = __iw;
    while (x) { T t = x / 10; char c = x - 10 * t + '0'; *__iw++ = c; x = t; }
    char* f = __iw - 1; while (s < f) {swap(*s, *f); ++s; --f;}
    if (__iw > __ew) {cout.write(__buw, __iw - __buw); __iw = __buw;}
    if (endc) { *__iw++ = endc; }
}
template<class T>
void writeStr(const T& str) {
    int i = 0; while (str[i]) { *__iw++ = str[i++]; if (__iw > __ew) {cout.write(__buw, __iw - __buw); __iw = __buw; }}
}
struct __FL__ { ~__FL__() { if (__iw != __buw) cout.write(__buw, __iw - __buw); } };
static __FL__ __flushVar__;

//STL output *****************************************************************************************************
#define TT1 template<class T>
#define TT1T2 template<class T1, class T2>
#define TT1T2T3 template<class T1, class T2, class T3>
#if __cplusplus >= 201703L
TT1T2 ostream& operator << (ostream& os, const pair<T1, T2>& p);
TT1T2T3 ostream& operator << (ostream& os, const triple<T1, T2, T3>& t);
TT1T2 ostream& operator << (ostream& os, priority_queue<T1, T2> v);
template <class Ch, class Tr, class Container>
basic_ostream <Ch, Tr> & operator << (basic_ostream <Ch, Tr> & os, const Container& x);
TT1T2 ostream& operator << (ostream& os, const pair<T1, T2>& p){ return os <<"("<<p.first<<", "<< p.second<<")"; }
TT1T2T3 ostream& operator << (ostream& os, const triple<T1, T2, T3>& t){ return os << "(" << t.a << ", " << t.b << ", " << t.c << ")"; }
TT1T2 void printarray(const T1& a, T2 sz, T2 beg = 0){ for (T2 i = beg; i<sz; i++) cout << a[i] << " "; cout << endl; }
TT1T2 ostream& operator << (ostream& os, priority_queue<T1, T2> v) {
    bool f = 1;
    os << "[";
    while (!v.empty()) {
        if (!f) os << ", ";
        f = 0; os << v.top();
        v.pop();
    }
    return os << "]";
}

template <class Ch, class Tr, class Container>
basic_ostream <Ch, Tr> & operator << (basic_ostream <Ch, Tr> & os, const Container& x) {
    if constexpr (std::is_pointer<Container>::value) {
        if constexpr (sizeof(*x) == 1) { return os << (const char*)x; } else { return os << (ptrdiff_t)x; }
    } else {
        os << "["; bool f = 1; for(const auto& y : x) { if (!f) os << ", "; f = 0; os << y; } return os << "]";
    }
}

//STL input *****************************************************************************************************
TT1T2T3 inline istream& operator >> (istream& os, triple<T1, T2, T3>& t);
TT1T2 inline istream& operator >> (istream& os, pair<T1, T2>& p) { return os >> p.first >> p.second; }
TT1 inline istream& operator >> (istream& os, vector<T>& v) {
    if (v.size()) for (T& t : v) os >> t; else {
        string s; T obj; while (s.empty()) {getline(os, s); if (!os) return os;}
        stringstream ss(s); while (ss >> obj) v.push_back(obj);
    }
    return os;
}
TT1T2T3 inline istream& operator >> (istream& os, triple<T1, T2, T3>& t) { return os >> t.a >> t.b >> t.c; }
#endif

//Pair magic *****************************************************************************************************
#define PT1T2 pair<T1, T2>
TT1T2 inline PT1T2 operator+(const PT1T2 &p1 , const PT1T2 &p2) { return PT1T2(p1.first + p2.first, p1.second + p2.second); }
TT1T2 inline PT1T2& operator+=(PT1T2 &p1 , const PT1T2 &p2) { p1.first += p2.first, p1.second += p2.second; return p1; }
TT1T2 inline PT1T2 operator-(const PT1T2 &p1 , const PT1T2 &p2) { return PT1T2(p1.first - p2.first, p1.second - p2.second); }
TT1T2 inline PT1T2& operator-=(PT1T2 &p1 , const PT1T2 &p2) { p1.first -= p2.first, p1.second -= p2.second; return p1; }

#undef TT1
#undef TT1T2
#undef TT1T2T3

#define FREIN(FILE) freopen(FILE, "rt", stdin)
#define FREOUT(FILE) freopen(FILE, "wt", stdout)
#ifdef LOCAL
#define BEGIN_PROFILE(idx, name) int profileIdx = idx; profileName[profileIdx] = name; totalTime[profileIdx] -= rdtsc() / 1e3;
#define END_PROFILE totalTime[profileIdx] += rdtsc() / 1e3; totalCount[profileIdx]++;
#else
#define BEGIN_PROFILE(idx, name)
#define END_PROFILE
#endif

const int USUAL_MOD = 1000000007;
template<class T> inline void normmod(T &x, T m = USUAL_MOD) { x %= m; if (x < 0) x += m; }
template<class T1, class T2> inline T2 summodfast(T1 x, T1 y, T2 m = USUAL_MOD) { T2 res = x + y; if (res >= m) res -= m; return res; }
template<class T1, class T2, class T3 = int> inline void addmodfast(T1 &x, T2 y, T3 m = USUAL_MOD) { x += y; if (x >= m) x -= m; }
template<class T1, class T2, class T3 = int> inline void submodfast(T1 &x, T2 y, T3 m = USUAL_MOD) { x -= y; if (x < 0) x += m; }
inline ll mulmod(ll x, ll n, ll m){ x %= m; n %= m; ll r = x * n - ll(ld(x)*ld(n) / ld(m)) * m; while (r < 0) r += m; while (r >= m) r -= m; return r; }
inline ll powmod(ll x, ll n, ll m){ ll r = 1; normmod(x, m); while (n){ if (n & 1) r *= x; x *= x; r %= m; x %= m; n /= 2; }return r; }
inline ll powmulmod(ll x, ll n, ll m) { ll res = 1; normmod(x, m); while (n){ if (n & 1)res = mulmod(res, x, m); x = mulmod(x, x, m); n /= 2; } return res; }
template<class T> inline T gcd(T a, T b) { while (b) { T t = a % b; a = b; b = t; } return a; }
template<class T>
T fast_gcd(T u, T v) {
    int shl = 0; while ( u && v && u != v) { T eu = u & 1; u >>= eu ^ 1; T ev = v & 1; v >>= ev ^ 1;
        shl += (~(eu | ev) & 1); T d = u & v & 1 ? (u + v) >> 1 : 0; T dif = (u - v) >> (sizeof(T) * 8 - 1); u -= d & ~dif; v -= d & dif;
    } return std::max(u, v) << shl;
}
template<class T> inline ll norm(const pair<T, T>& p) {
    return p.first * 1LL * p.first + p.second * 1LL * p.second;
}
inline ll lcm(ll a, ll b){ return a / gcd(a, b) * b; }
template<class T> inline T gcd(T a, T b, T c){ return gcd(gcd(a, b), c); }
ll gcdex(ll a, ll b, ll& x, ll& y) {
    if (!a) { x = 0; y = 1; return b; }
    ll y1; ll d = gcdex(b % a, a, y, y1); x = y1 - (b / a) * y;
    return d;
}

bool isPrime(long long n) {
    if (n <= (1 << 14)) { int x = (int) n; if (x <= 4 || x % 2 == 0 || x % 3 == 0) return x == 2 || x == 3;
        for (int i = 5; i * i <= x; i += 6) if (x % i == 0 || x % (i + 2) == 0) return 0; return 1; }
    long long s = n - 1; int t = 0; while (s % 2 == 0) { s /= 2; ++t; }
    for (int a : {2, 325, 9375, 28178, 450775, 9780504, 1795265022}) { if (!(a %= n)) return true;
        long long f = powmulmod(a, s, n); if (f == 1 || f == n - 1) continue;
        for (int i = 1; i < t; ++i) if ((f = mulmod(f, f, n)) == n - 1) goto nextp;
        return false; nextp:;
    } return true;
}

// Useful constants

//int some_primes[7] = {24443, 100271, 1000003, 1000333, 5000321, 98765431,
#define T9          1000000000
#define T18         1000000000000000000LL
#define INF         1011111111
#define LLINF       1000111000111000111LL
#define mod         1000000007
#define fftmod      998244353
#define EPS         1e-10
#define PI          3.14159265358979323846264
#define link        hiallisubmitted
#define rank        thatsnoteasytask
//*************************************************************************************

int32_t solve();
int32_t main(int argc, char** argv) {
    ios_base::sync_with_stdio(0);cin.tie(0);
#ifdef LOCAL
    FREIN("Data/input.txt");
//    FREOUT("Data/output.txt");
#endif
    return solve();
}

bitset<1000> g[1000];
int a[1010][505];
int cnt[505][505];
int n;
bool anySame(const int *a, const int *b) {
    bool ok = false;
    for (int i = 0; i < n; ++i) {
        ok |= a[i] == b[i];
    }
    return ok;
}
//int color[1010];
//int cnt[4] = {};
//void go(int cur, int c) {
//    color[cur] = c;
//    cnt[c]++;
//    for (int i = 0; i < 2 * n; ++i) {
//        if (g[cur][i] && !color[i]) {
//            go(i, 3 - c);
//        }
//    }
//}
char good[1010];
char bad[1010];
void goGood(int cur);
void goBad(int cur);
vector<int> v[505][505];
void goBad(int cur) {
    if (bad[cur] >= 2) {
        return;
    }
    bad[cur] = 2;
    assert(!good[cur]);
//    DBN("goBad", cur);
    for (int i = 0; i < n; ++i) {
        int x = a[cur][i];
        cnt[i][x]--;
        if (cnt[i][x] == 1) {
            for (int t : v[i][x]) {
                if (!bad[t]) {
//                    DBN(cur, "goGood", t);
                    goGood(t);
                }
            }
        }
    }
}
void goGood(int cur) {
    if (good[cur] >= 2) {
        return;
    }
    good[cur] = 2;
    assert(!bad[cur]);
//    DBN("goGood", cur);
    for (int i = 0; i < 2 * n; ++i) {
        if (g[cur][i]) {
            goBad(i);
        }
    }
    for (int i = 0; i < 2 * n; ++i) {
        if (g[cur][i]) {
//            DBN(cur, "goBad", i);
            
        }
    }
}
bool used[2010];
vector<int> res;
void go(int cur, bool take) {
    used[cur] = true;
    if (take) {
        res.push_back(cur);
    }
    for (int i = 0; i < 2 * n; ++i) {
        if (g[cur][i] && !used[i] && !good[i] && !bad[i]) {
            go(i, !take);
        }
    }
}
int dp[1010][1010];
int solve() {
    int tc = readInt();
    while (tc--) {
        n = readInt();
        for (int i = 0; i < 2 * n; ++i) {
            good[i] = false;
        }
        for (int i = 0; i < 2 * n; ++i) {
            bad[i] = false;
        }
        for (int i = 0; i < 2 * n; ++i) {
            used[i] = false;
        }
        for (int i = 0; i < 2 * n; ++i) {
            for (int j = 0; j < n; ++j) {
                a[i][j] = readInt() - 1;
                cnt[j][a[i][j]]++;
                v[j][a[i][j]].push_back(i);
            }
        }
        for (int i = 0; i < 2 * n; ++i) {
            for (int j = 0; j < i; ++j) {
                g[i][j] = g[j][i] = anySame(a[i], a[j]);
            }
        }
        for (int i = 0; i < 2 * n; ++i) {
            if (bad[i]) continue;
            if (good[i]) continue;
            for (int j = 0; j < n; ++j) {
                if (cnt[j][a[i][j]] == 1) {
                    goGood(i);
                    break;
                }
            }
        }
        int ans = 1;
        res.clear();
        for (int i = 0; i < 2 * n; ++i) {
            if (good[i] || bad[i] || used[i]) continue;
            go(i, true);
            ans = ans * 1LL * 2 % fftmod;
        }
        FI(n) FJ(n) v[i][j].clear();
        FI(n) FJ(n) cnt[i][j] = 0;
        cout << ans << endl;
        FI(2 * n) {
            if (good[i]) {
                res.push_back(i);
            }
        }
        assert(res.size() == n);
        for (int x : res) {
            cout << x + 1 << ' ';
        }
        cout << endl;
    }
    
    
    return 0;
}