#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvl = vector<vll>;
using pll = pair<ll,ll>;
#define f first
#define s second
#define pb push_back
#define all(v) v.begin(),v.end()
const int mod = 998244353;
int main(){
ios_base::sync_with_stdio(0);cin.tie(NULL);
ll n, m;
cin >> n >> m;
vvl g(n);
for(ll a,b,i = 0; i < m; ++i){
cin >> a >> b;
g[--a].pb(--b);
}
vll dp(1<<n);
vll fac(n+1, 1);
for(ll i = 1; i <= n; ++i)fac[i]=(fac[i-1]*i)%mod;
for(ll i = 1; i < (1<<n); ++i){
ll mul = fac[__builtin_popcount(i)-1];
for(ll j = 0; j < n; ++j){
if(!(i & (1<<j)))continue;
dp[i] += dp[i^(1<<j)];
dp[i] %= mod;
for(ll x:g[j]){
if(i&(1<<x))dp[i]+=mul;
}
dp[i]%=mod;
}
}
cout << dp.back();
}
