#include <iostream>
#include <vector>
#include <algorithm>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
using ll = long long;
#define REP(i, n) for(ll i=0; i<(n);i++)
#define PER(i, n) for(ll i=n-1; i>=0;i--)

int main() {
  ll n, m;
  cin >> n >> m;

  if (n % 2) {
    cout << 0;
    return 0;
  }

  vector<mint> f(n + 1, 1), rf(n + 1, 1);
  REP(i, n) {
    f[i + 1] = f[i] * (i + 1);
    rf[i + 1] = mint(1) / f[i + 1];
  }

  vector<vector<mint>> dps={{1}};
  REP(i, m) {
    ll l, r;
    cin >> l >> r;
    if((r-l)%2){
    	ll d=(r-l+1)/2;
    	vector<mint> add(d+1);
    	add[0]=1;
    	add[d]=-f[d*2]*rf[d]*rf[d]/(d+1);
    	dps.push_back(add);
    }
  }

  while(dps.size()>1){
  	vector<vector<mint>> ndps;
  	REP(i,dps.size() / 2){
  		ndps.push_back(convolution(dps[i*2],dps[i*2+1]));
  	}
  	if(dps.size()%2){
  		ndps.push_back(dps.back());
  	}
  	swap(dps,ndps);
  }

  mint ans = 0;
  REP(i, dps[0].size()) {
    ans += dps[0][i] * f[n - i * 2] * rf[n / 2 - i] * rf[n / 2 - i] / (n / 2 - i + 1);
  }
  cout << ans.val();

  return 0;
}