#include<bits/stdc++.h>

#define rep(i, j, n) for(ll i = ll(j); i < ll(n); i++)
#define REP(i, j, n) for(ll i = ll(j); i <= ll(n); i++)
#define per(i, j, n) for(ll i = ll(j); ll(n) <= i; i--)
#define ALL(a) (a).begin(),(a).end()
#define revALL(a) (a).rbegin(),(a).rend()
#define pb emplace_back
#define mp std::make_pair
#define mtp std::make_tuple
#define ln "\n"

using std::endl;
using std::cin;
using std::cout;
using ll = long long;
using std::vector;
using std::string;
using vi = vector<ll>;
using vii = vector<vi>;
using pii = std::pair<ll, ll>;

constexpr ll MOD = 998244353;
constexpr ll MAX = 1e6+10;
constexpr ll inf = (1ll << 60);

//binom_init, binom
vi fac,finv,inv;
void binom_init() {
    fac.resize(MAX);
    finv.resize(MAX);
    inv.resize(MAX);
    fac[0] = fac[1] = 1;
    inv[1] = 1;
    finv[0] = finv[1] = 1;
    rep(i, 2, MAX){
        fac[i] = fac[i-1]*i%MOD;
        inv[i] = MOD-MOD/i*inv[MOD%i]%MOD;
        finv[i] = finv[i-1]*inv[i]%MOD;
    }
}
ll binom(ll n, ll r){
    if(n<r || n<0 || r<0) return 0;
    return fac[n]*finv[r]%MOD*finv[n-r]%MOD;
}

//main
int main(){
    binom_init();
    ll N,Q; cin >> N >> Q;
    vi sum(N+1);
    vi l(Q), r(Q);
    rep(i,0,Q){
        ll L,R; cin >> L >> R;
        sum[L-1] ^= (1ll<<i);
        sum[R] ^= (1ll<<i);
        l[i] = L, r[i] = R;
    }
    ll ans = fac[N/2]*fac[N-N/2]%MOD;
    {
        std::set<ll> set;
        rep(i,0,Q) set.insert(l[i]-1), set.insert(r[i]);
        set.insert(0);
        set.insert(N);
        vi data(ALL(set));
        ll cnt2 = 0;
        rep(i,1,data.size()){
            ll length = data[i]-data[i-1];
            if(length%2) cnt2++;
        }
        if(cnt2 > 1) ans = 0;
    }
    rep(i,0,N) sum[i+1] ^= sum[i];
    std::map<ll,ll> cnt;
    rep(i,0,N) cnt[sum[i]]++;
    for(auto el: cnt){
        if(el.second%2){
            ans *= binom(el.second+1,(el.second+1)/2)*inv[(el.second+1)/2+1]%MOD;
        }
        else ans *= binom(el.second,el.second/2)*inv[el.second/2+1]%MOD;
        ans %= MOD;
    }
    cout << ans << ln;
}