#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double Double;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

// chmax, chmin
template<class T>
inline bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}

template<class T>
inline bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}

const long long MOD = 998244353;


template<typename T>
class FenwickTree {
    const int n;
    std::vector<T> data;

public:
    FenwickTree(int count) : n(count), data(count, 0) { ; }

    void add(int pos, const T &value) {
        assert(0 <= pos && pos < n);
        for (int i = pos; i < n; i |= i + 1) data[i] += value;
    }

    // 区間 [0, pos) 番目の範囲の和を求める．(pos = 0 のときは 0 を返す．)
    T sum(int pos) const {
        assert(0 <= pos && pos <= n);
        T res = 0;
        for (int i = pos - 1; i >= 0; i = (i & (i + 1)) - 1) {
            res += data[i];
        }
        return res;
    }

    // 区間 [l, r) 番目の範囲の和を求める．(l = r のときは 0 を返す．)
    T sum(int l, int r) const {
        assert(0 <= l && l <= r && r <= n);
        return sum(r) + (-sum(l));
    }

    using value_type = T;
    using update_type = T;
};


template<int M, bool IsPrime = false>
class Modulo {
    int n;

    static typename std::enable_if<IsPrime, ll>::type inv(ll a, ll p) {
        return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
    }

public:
    Modulo() : n(0) { ; }

    Modulo(int m) : n(m) {
        if (n >= M)
            n %= M;
        else if (n < 0)
            n = (n % M + M) % M;
    }

    Modulo(ll m) {
        if (m >= M)
            m %= M;
        else if (m < 0)
            m = (m % M + M) % M;
        n = m;
    }

    explicit operator int() const { return n; }

    explicit operator ll() const { return n; }

    bool operator==(const Modulo &a) const { return n == a.n; }

    Modulo &operator+=(const Modulo &a) {
        n += a.n;
        if (n >= M) n -= M;
        return *this;
    }

    Modulo &operator-=(const Modulo &a) {
        n -= a.n;
        if (n < 0) n += M;
        return *this;
    }

    Modulo &operator*=(const Modulo &a) {
        n = (ll(n) * a.n) % M;
        return *this;
    }

    Modulo operator+(const Modulo &a) const {
        Modulo res = *this;
        return res += a;
    }

    Modulo operator-(const Modulo &a) const {
        Modulo res = *this;
        return res -= a;
    }

    Modulo operator-() const { return Modulo(0) - *this; }

    Modulo operator*(const Modulo &a) const {
        Modulo res = *this;
        return res *= a;
    }

    Modulo operator^(ll m) const {
        if (m == 0) return Modulo(1);
        const Modulo a = *this;
        Modulo res = (a * a) ^(m / 2);
        return m % 2 ? res * a : res;
    }

    typename std::enable_if<IsPrime, Modulo>::type
    operator/(const Modulo &a) const {
        return *this * inv(ll(a), M);
    }

    typename std::enable_if<IsPrime, Modulo>::type operator/=(const Modulo &a) {
        return *this *= inv(ll(a), M);
    }

    friend bool is_zero(const Modulo &x) { return int(x) == 0; }

    friend int abs(const Modulo &x) { return int(x); }

    static Modulo fact(int n, bool sw = true) {
        static std::vector<Modulo> v1 = {1}, v2 = {1};
        if (n >= (int) v1.size()) {
            const int from = v1.size(), to = n + 1024;
            v1.reserve(to);
            v2.reserve(to);
            for (int i = from; i < to; ++i) {
                v1.push_back(v1.back() * Modulo<M, true>(i));
                v2.push_back(v2.back() / Modulo<M, true>(i));
            }
        }
        return sw ? v1[n] : v2[n];
    }

    static Modulo comb(int a, int b) {
        if (b < 0 || b > a) return 0;
        return Modulo::fact(a, true) * Modulo::fact(b, false) *
               Modulo::fact(a - b, false);
    }
};

typedef Modulo<998244353, true> mInt;


void solve(long long N, long long K, std::vector<long long> L,
           std::vector<long long> R) {

    FenwickTree<mInt> seg(N + 10);

    seg.add(1, 1);
    seg.add(2, -1);

    for (int i = 1; i <= N; i++) {
        mInt val = seg.sum(i+1);
        for (int k = 0; k < K; k++) {
            int a = i + L[k];
            int b = min(N + 1, i + R[k] + 1);
            if (a > N) continue;
            seg.add(a, val);
            seg.add(b, -val);
        }
    }
    cout << (int) seg.sum(N + 1) << endl;

}

int main() {
    long long N;
    scanf("%lld", &N);
    long long K;
    scanf("%lld", &K);
    std::vector<long long> L(K);
    std::vector<long long> R(K);
    for (int i = 0; i < K; i++) {
        scanf("%lld", &L[i]);
        scanf("%lld", &R[i]);
    }
    solve(N, K, std::move(L), std::move(R));
    return 0;
}


Measured memory_bytes: 4060