#include <bits/stdc++.h>
// #include <atcoder/all>

using namespace std;
// using namespace atcoder;

using ll = long long;
using P = pair<ll, ll>;
using Graph = vector<vector<ll>>;
#define rep(i, n) for(ll i=0;i<(ll)(n);i++)
#define rep2(i, m, n) for(ll i=m;i<(ll)(n);i++)
#define rrep(i, n, m) for(ll i=n;i>=(ll)(m);i--)
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const int ddx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
const int ddy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll MOD = 998244353;
const ll INF = 1000000000000000000L;
#ifdef __DEBUG

/**
 * For DEBUG
 * https://github.com/ta7uw/cpp-pyprint
 */
#include "cpp-pyprint/pyprint.h"

#endif

class mint {
public:
    long long x;

    constexpr mint(long long x = 0) : x((x % MOD + MOD) % MOD) {}

    constexpr mint operator-() const {
        return mint(-x);
    }

    constexpr mint &operator+=(const mint &rhs) {
        if ((x += rhs.x) >= MOD) x -= MOD;
        return *this;
    }

    constexpr mint &operator-=(const mint &rhs) {
        if ((x += MOD - rhs.x) >= MOD) x -= MOD;
        return *this;
    }

    constexpr mint &operator*=(const mint &rhs) {
        (x *= rhs.x) %= MOD;
        return *this;
    }

    constexpr mint operator+(const mint &rhs) const {
        mint res(*this);
        return res += rhs;
    }

    constexpr mint operator-(const mint &rhs) const {
        mint res(*this);
        return res -= rhs;
    }

    constexpr mint operator*(const mint &rhs) const {
        mint res(*this);
        return res *= rhs;
    }

    [[nodiscard]] constexpr mint pow(long long t) const {
        if (!t) return 1;
        mint a = pow(t >> 1);
        a *= a;
        if (t & 1) a *= *this;
        return a;
    }

    [[nodiscard]] constexpr mint inv() const {
        return pow(MOD - 2);
    }

    mint &operator/=(mint rhs) {
        return *this *= rhs.inv();
    }

    mint operator/(const mint rhs) const {
        return mint(*this) /= rhs;
    }

    constexpr bool operator==(const mint &rhs) const noexcept {
        return this->x == rhs.x;
    }

    constexpr bool operator!=(const mint &rhs) const noexcept {
        return this->x != rhs.x;
    }

    bool operator<(const mint &rhs) const noexcept {
        return this->x < rhs.x;
    }

    bool operator>(const mint &rhs) const noexcept {
        return this->x > rhs.x;
    }

    bool operator<=(const mint &rhs) const noexcept {
        return this->x <= rhs.x;
    }

    bool operator>=(const mint &rhs) const noexcept {
        return this->x >= rhs.x;
    }

    friend istream &operator>>(istream &is, mint &a) {
        long long t;
        is >> t;
        a = mint(t);
        return is;
    }

    friend ostream &operator<<(ostream &os, const mint &a) {
        return os << a.x;
    }
};

template<class Monoid>
class SegmentTree {

public:
    /**
     * @param N size
     * @param e identity element
     * @param operation operation to merge `data`
     * @param updater operation to update `data`
     */
    SegmentTree(size_t N, Monoid e, function<Monoid(Monoid, Monoid)> operation,
                function<Monoid(Monoid, Monoid)> updater)
            : e(e), operation(operation), updater(move(updater)) {
        n = 1;
        while (n < N) {
            n *= 2;
        }
        data = vector<Monoid>(2 * n - 1, e);
        for (int i = n - 2; i >= 0; i--) {
            data[i] = operation(data[2 * i + 1], data[2 * i + 2]);
        }
    }

    /**
     * iの値をxに更新 ( 0-indexed )
     */
    void update(int i, Monoid x) {
        i += n - 1;
        data[i] = updater(data[i], x);
        while (i > 0) {
            i = (i - 1) / 2;
            data[i] = operation(data[i * 2 + 1], data[i * 2 + 2]);
        }
    }

    /**
     * [a, b)の区間でクエリを実行
     */
    Monoid query(int a, int b) {
        return query(a, b, 0, 0, n);
    }

    /**
     * 添字でアクセス( 0-indexed )
     */
    Monoid operator[](int i) {
        return data[i + n - 1];
    }

private:
    int n;
    vector<Monoid> data;
    Monoid e;
    function<Monoid(Monoid, Monoid)> operation;
    function<Monoid(Monoid, Monoid)> updater;

    Monoid query(int a, int b, int k, int l, int r) {
        // 交差しない
        if (r <= a || b <= l) return e;
        // 区間 [a, b) に l, r が含まれる
        if (a <= l && r <= b) return data[k];
        // 左の子
        Monoid c1 = query(a, b, 2 * k + 1, l, (l + r) / 2);
        // 右の子
        Monoid c2 = query(a, b, 2 * k + 2, (l + r) / 2, r);
        return operation(c1, c2);
    }
};


void solve() {
    ll N, K;
    cin >> N >> K;
    vector<P> items(K);
    rep(i, K) cin >> items[i].first >> items[i].second;
    SegmentTree<mint> sg(N + 19, 0, [](mint a, mint b) {
        return a + b;
    }, [](mint a, mint b) {
        return b;
    });
    sg.update(1, 1);
    rep2(i, 2, N + 1) {
        mint now = sg.query(i, i + 1);
        rep(j, K) {
            P p = items[j];
            ll l = p.first;
            ll r = p.second;
            now += sg.query(max(0LL, i - r), max(1LL, i - l + 1));
        }
//        cout << sg.query(0, 10) << '\n';
//        print(i, now.x);
        sg.update(i, now);
    }
    cout << sg.query(N, N + 1) << '\n';
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    solve();
    return 0;
}


Measured memory_bytes: 7428