#include <bits/stdc++.h>
const int Mod = 998244353;
int bit[21];
long long root[21], root_inv[21];
long long div_mod(long long x, long long y, long long z) {
  if (x % y == 0)
    return x / y;
  else
    return (div_mod((1 + x / y) * y - x, (z % y), y) * z + x) / y;
}
long long pow_mod(long long n, int k) {
  long long N, ans = 1;
  for (N = n; k > 0; k >>= 1, N = N * N % Mod)
    if (k & 1) ans = ans * N % Mod;
  return ans;
}
void NTT(int k, long long a[], long long z[]) {
  if (k == 0) {
    z[0] = a[0];
    return;
  }
  int i, d = bit[k - 1];
  long long tmp, *b = (long long *)malloc(sizeof(long long) * d),
                 *c = (long long *)malloc(sizeof(long long) * d),
                 *x = (long long *)malloc(sizeof(long long) * d),
                 *y = (long long *)malloc(sizeof(long long) * d);
  for (i = 0; i < d; i++) {
    b[i] = a[i * 2];
    c[i] = a[i * 2 + 1];
  }
  NTT(k - 1, b, x);
  NTT(k - 1, c, y);
  for (i = 0, tmp = 1; i < d; i++, tmp = tmp * root[k] % Mod) {
    z[i] = (x[i] + y[i] * tmp) % Mod;
    z[i + d] = (x[i] - y[i] * tmp % Mod + Mod) % Mod;
  }
  free(b);
  free(c);
  free(x);
  free(y);
}
void NTT_reverse(int k, long long z[], long long a[]) {
  if (k == 0) {
    a[0] = z[0];
    return;
  }
  int i, d = bit[k - 1];
  long long tmp, *b = (long long *)malloc(sizeof(long long) * d),
                 *c = (long long *)malloc(sizeof(long long) * d),
                 *x = (long long *)malloc(sizeof(long long) * d),
                 *y = (long long *)malloc(sizeof(long long) * d);
  for (i = 0; i < d; i++) {
    x[i] = z[i * 2];
    y[i] = z[i * 2 + 1];
  }
  NTT_reverse(k - 1, x, b);
  NTT_reverse(k - 1, y, c);
  for (i = 0, tmp = 1; i < d; i++, tmp = tmp * root_inv[k] % Mod) {
    a[i] = (b[i] + c[i] * tmp) % Mod;
    a[i + d] = (b[i] - c[i] * tmp % Mod + Mod) % Mod;
  }
  free(b);
  free(c);
  free(x);
  free(y);
}
void prod_poly_NTT(int d, long long a[], long long b[], long long c[]) {
  int i, k;
  for (k = 0, bit[0] = 1; bit[k] < d; k++) bit[k + 1] = bit[k] * 2;
  for (i = k - 1, root[k] = pow_mod(3, (Mod - 1) / bit[k]),
      root_inv[k] = pow_mod(3, Mod - 1 - (Mod - 1) / bit[k]);
       i >= 0; i--) {
    root[i] = root[i + 1] * root[i + 1] % Mod;
    root_inv[i] = root_inv[i + 1] * root_inv[i + 1] % Mod;
  }
  long long *x = (long long *)malloc(sizeof(long long) * bit[k]),
            *y = (long long *)malloc(sizeof(long long) * bit[k]),
            *z = (long long *)malloc(sizeof(long long) * bit[k]);
  NTT(k, a, x);
  NTT(k, b, y);
  for (i = 0; i < bit[k]; i++) z[i] = x[i] * y[i] % Mod;
  NTT_reverse(k, z, c);
  for (i = 0; i < d; i++) c[i] = div_mod(c[i], bit[k], Mod);
  free(x);
  free(y);
  free(z);
}
void merge_sort(int x[], int n) {
  static int y[100001] = {};
  if (n <= 1) return;
  merge_sort(&(x[0]), n / 2);
  merge_sort(&(x[n / 2]), (n + 1) / 2);
  int i, p, q;
  for (i = 0, p = 0, q = n / 2; i < n; i++) {
    if (p >= n / 2)
      y[i] = x[q++];
    else if (q >= n)
      y[i] = x[p++];
    else
      y[i] = (x[p] < x[q]) ? x[p++] : x[q++];
  }
  for (i = 0; i < n; i++) x[i] = y[i];
}
int main() {
  int h, i, N, num[100001] = {};
  scanf("%d", &N);
  N *= 2;
  for (i = 1; i <= N; i++) {
    scanf("%d", &h);
    num[h]++;
  }
  merge_sort(num, 100001);
  long long fact[100001], fact_inv[100001], pow[100001], pow_inv[100001];
  for (i = 1, fact[0] = 1; i <= N; i++) fact[i] = fact[i - 1] * i % Mod;
  for (i = N - 1, fact_inv[N] = div_mod(1, fact[N], Mod); i >= 0; i--)
    fact_inv[i] = fact_inv[i + 1] * (i + 1) % Mod;
  for (i = 1, pow[0] = 1; i <= N; i++) pow[i] = pow[i - 1] * 2 % Mod;
  for (i = N - 1, pow_inv[N] = div_mod(1, pow[N], Mod); i >= 0; i--)
    pow_inv[i] = pow_inv[i + 1] * 2 % Mod;
  int d, j, k, l;
  long long ans = fact[N] * fact_inv[N / 2] % Mod * pow_inv[N / 2] % Mod;
  long long a[3][262144] = {};
  for (i = 0, j = 0, d = 1, a[0][0] = 1; i <= 100000; i++) {
    if (num[i] < 2) continue;
    for (k = 0; k <= num[i] / 2; k++)
      a[2][k] = fact[num[i]] * fact_inv[num[i] - k * 2] % Mod * pow_inv[k] %
                Mod * fact_inv[k] % Mod;
    if ((long long)d * (num[i] / 2) > 100000)
      prod_poly_NTT(d + num[i] / 2 + 1, a[j], a[2], a[j ^ 1]);
    else {
      for (k = 0; k <= d + num[i] / 2; k++) a[j ^ 1][k] = 0;
      for (k = 0; k < d; k++) {
        for (l = 0; l <= num[i] / 2; l++)
          a[j ^ 1][k + l] = (a[j ^ 1][k + l] + a[j][k] * a[2][l]) % Mod;
      }
    }
    j ^= 1;
    d += num[i] / 2;
  }
  for (i = 1; i < d; i++) {
    if (i % 2 == 1)
      ans = (ans + (Mod - a[j][i]) * fact[N - i * 2] % Mod *
                       fact_inv[N / 2 - i] % Mod * pow_inv[N / 2 - i]) %
            Mod;
    else
      ans = (ans + a[j][i] * fact[N - i * 2] % Mod * fact_inv[N / 2 - i] % Mod *
                       pow_inv[N / 2 - i]) %
            Mod;
  }
  printf("%lld\n", ans);
  fflush(stdout);
  return 0;
}
