#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int M = 998244353;
int add(int a, int b)
{
a += b;
if (a >= M)
{
return a - M;
}
if (a < 0)
{
return a + M;
}
return a;
}
int mul(int a, int b)
{
return a * (ll) b % M;
}
int pw(int a, int b)
{
int r = 1;
while (b)
{
if (b & 1)
{
r = mul(r, a);
}
a = mul(a, a);
b /= 2;
}
return r;
}
int dv(int a, int b)
{
return mul(a, pw(b, M - 2));
}
void addup(int &a, int b)
{
a = add(a, b);
}
void mulup(int &a, int b)
{
a = mul(a, b);
}
const int N = 18;
int n;
int m;
int g[N];
vector<pair<int, int>> dp_push[1 << N];
int dp[1 << N];
int main()
{
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
/**
query = what is the sum(of number of inverted edges for every possible choice of edges directions)
we have
# inverted edges(ordering) = m - # inverted edges(~ordering)
bijection =>
query = # possible choice of edges directions * m / 2
**/
cin >> n >> m;
for (int i = 0; i < m; i++)
{
int a, b;
cin >> a >> b;
a--;
b--;
assert(0 <= a && a < n);
assert(0 <= b && b < n);
g[a] |= (1 << b);
g[b] |= (1 << a);
}
int sol = 0;
dp_push[(1 << n) - 1].push_back({(1 << n) - 1, 1});
vector<int> sub_masks;
for (int rem_verts = (1 << n) - 1; rem_verts > 0; rem_verts--)
{
{
sub_masks.clear();
for (int i = rem_verts; i; i = (i - 1) & rem_verts)
{
sub_masks.push_back(i);
}
sub_masks.push_back(0);
}
for (auto &it : dp_push[rem_verts])
{
addup(dp[it.first], it.second);
}
for (auto &possible_next : sub_masks)
{
if (int coef = dp[possible_next])
{
for (int vertex = 0; vertex < n; vertex++)
{
if (possible_next & (1 << vertex))
{
dp_push[rem_verts - (1 << vertex)].push_back({(possible_next & ((1 << vertex) - 1)) | (g[vertex] & rem_verts), coef});
}
}
dp[possible_next] = 0;
}
}
}
for (auto &it : dp_push[0]) {
addup(sol, it.second);
}
cout << mul(sol, dv(m, 2)) << "\n";
}
