#define _CRT_SECURE_NO_WARNINGS
#pragma comment(linker, "/stack:512000000")
#include<utility>
#include<iostream>
#include<fstream>
#include<vector>
#include<array>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<ctime>
#include<functional>
#include<random>
#include<climits>
#include<queue>
#include<stack>
#include<deque>
#include<bitset>
#include<map>
#include<set>
#include<unordered_map>
#include<unordered_set>
#include<cassert>
#include<ccomplex>
#include<chrono>

#ifdef ONLINE_JUDGE
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
#pragma GCC optimize("unroll-loops")
#define int128 __int128
#else
#define int128 long long
#endif

#define all(x) x.begin(), x.end()
#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
#define mp make_pair
#define X first
#define Y second

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
mt19937_64 gen(time(nullptr));

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

ll mod = 1e9 + 7;

namespace {
    ll mul(ll a, ll b) {
        ll val = a * b - (ll)((ld)a * b / mod) * mod;
        if (val < 0) val += mod;
        if (val >= mod) val -= mod;
        return val;
    }
    ll poww(ll a, ll b) {
        ll val = 1;
        a %= mod;
        while (b > 0) {
            if (b % 2) val = mul(a, val);
            a = mul(a, a);
            b >>= 1;
        }
        return val % mod;
    }
    ll inv(ll a) {
        return poww(a, mod - 2);
    }
    ll gcd(ll a, ll b) {
        return (a == 0 ? b : gcd(b % a, a));
    }
    ll gcdex(ll a, ll b, ll& x, ll& y) {
        if (a == 0) {
            x = 0; y = 1;
            return b;
        }
        ll x1, y1;
        ll d = gcdex(b % a, a, x1, y1);
        x = y1 - (b / a) * x1;
        y = x1;
        return d;
    }

    ll inv_eu(ll a, ll m) {
        ll x, y;
        ll g = gcdex(a, m, x, y);
        if (g != 1)
            assert(0);
        else {
            x = (x % m + m) % m;
            return x;
        }
    }
}

ll const maxn = 1e6 + 6;

ll fw[maxn];

void upd(ll r, ll add) {
    for (++r; r < maxn; r += -r & r) {
        (fw[r] += add) %= mod;
        if (fw[r] < 0) fw[r] += mod;
    }    
}

void upd(ll l, ll r, ll add) {
    upd(r + 1, -add);
    upd(l, add);
}


ll get(ll pos) {
    ll ret = 0;
    for (++pos; pos > 0; pos -= -pos & pos) {
        (ret += fw[pos]) %= mod;
    }
    return ret;
}


signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    mod = 998244353;
    ll n, k; cin >> n >> k;
    vector<pair<ll, ll>> s(k);
    for (ll i = 0; i < k; i++) {
        cin >> s[i].X >> s[i].Y;
    }

    upd(1, 1, 1);
    for (ll i = 1; i <= n; i++) {
        for (auto& p : s) {
            ll l = p.X, r = p.Y;
            upd(i + l, i + r, get(i));
        }
    }

    cout << get(n) << endl;
        
    return 0;
}

/*

*/

Measured memory_bytes: 6700