#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<numeric>
#include<cmath>
#include<utility>
#include<tuple>
#include<cstdint>
#include<cstdio>
#include<iomanip>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<deque>
#include<unordered_map>
#include<unordered_set>
#include<bitset>
#include<cctype>
#include<chrono>
#include<random>
#include<cassert>
#include<cstddef>
#include<iterator>
#include<string_view>
#include<type_traits>

#ifdef LOCAL
#  include "debug_print.hpp"
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
#define rrep(i,n) for(int i=(n)-1; i>=0; i--)
#define FOR(i,a,b) for(int i=(a); i<(b); i++)
#define RFOR(i,a,b) for(int i=(b-1); i>=(a); i--)
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define pb push_back
using ll = long long;
using D = double;
using LD = long double;
using P = pair<int, int>;
template<typename T> using PQ = priority_queue<T,vector<T>>;
template<typename T> using minPQ = priority_queue<T, vector<T>, greater<T>>;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
void yesno(bool flag) {cout << (flag?"Yes":"No") << "\n";}

template<typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    os << p.first << " " << p.second;
    return os;
}
template<typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p) {
    is >> p.first >> p.second;
    return is;
}

template<typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    int s = (int)v.size();
    for (int i = 0; i < s; i++) os << (i ? " " : "") << v[i];
    return os;
}
template<typename T>
istream &operator>>(istream &is, vector<T> &v) {
    for (auto &x : v) is >> x;
    return is;
}
void in() {}
template<typename T, class... U>
void in(T &t, U &...u) {
    cin >> t;
    in(u...);
}
void out() { cout << "\n"; }
template<typename T, class... U, char sep = ' '>
void out(const T &t, const U &...u) {
    cout << t;
    if (sizeof...(u)) cout << sep;
    out(u...);
}
void outr() {}
template<typename T, class... U, char sep = ' '>
void outr(const T &t, const U &...u) {
    cout << t;
    outr(u...);
}

#include "atcoder/modint.hpp"
#include "atcoder/convolution.hpp"

using mint = atcoder::modint998244353;

constexpr int mod = 998244353;

constexpr int mx = 200005;
mint fact[mx];
mint inv[mx];
mint finv[mx];

mint comb(int n, int m){
    if(n < 0 or m < 0 or n < m) return 0;
    return fact[n] * finv[m] * finv[n-m];
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,m; in(n,m);
    rep(i,mx) fact[i] = inv[i] = finv[i] = 1;
    for(int i = 2; i < mx; i++){
        fact[i] = fact[i-1] * i;
        inv[i] = -inv[mod%i] * (mod/i);
        finv[i] = finv[i-1] * inv[i];
    }

    vector<int> l(m),r(m);
    rep(i,m) in(l[i],r[i]);

    vector<mint> cat(n+1);
    rep(i,n+1) if(i%2==0) cat[i] = comb(i,i/2) * inv[i/2+1];

    queue<vector<mint>> q;
    rep(i,m){
        vector<mint> f(r[i]-l[i]+2);
        f[0] = 1;
        f[r[i]-l[i]+1] = -cat[r[i]-l[i]+1];
        q.push(f);
    }
    if(m == 0){
        out(cat[n].val());
        return 0;
    }

    while(q.size() > 1){
        auto f = q.front(); q.pop();
        auto g = q.front(); q.pop();
        q.push(atcoder::convolution(f,g));
    }

    int md = q.front().size();
    mint ans = 0;
    rep(i,md){
        ans += q.front()[i] * cat[n-i];
    }
    out(ans.val());
}