#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
#define all(n) begin(n), end(n)
const long long INF = numeric_limits<long long>::max();
typedef long long ll;
typedef vector<int> vint;
typedef vector<vector<int>> vvint;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef unsigned long long ull;
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;
}
template <typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }

template <typename T, typename... Ts>
auto make_v(size_t a, Ts... ts)
{
    return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}
template <typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type
fill_v(T &t, const V &v) { t = v; }

template <typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type
fill_v(T &t, const V &v)
{
    for (auto &e : t)
        fill_v(e, v);
}
const int MAX_N = 1e6 + 1;
vector<long long> factorialMemo(MAX_N, -1);        //factorialMemo[i] := i! mod p
vector<long long> inverseFactorialMemo(MAX_N, -1); // inverseFactorialMemo[i] := (factorialMemo[i])^(-1)
bool initFinished = false;
template <long long mod>
struct ModInt
{
    long long x;

    ModInt() : x(0) {}

    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    ModInt &operator+=(const ModInt &p)
    {
        if ((x += p.x) >= mod)
            x -= mod;
        return *this;
    }

    ModInt &operator-=(const ModInt &p)
    {
        if ((x += mod - p.x) >= mod)
            x -= mod;
        return *this;
    }

    ModInt &operator*=(const ModInt &p)
    {
        x = (1LL * x * p.x % mod);
        return *this;
    }

    ModInt &operator/=(const ModInt &p)
    {
        *this *= p.inverse();
        return *this;
    }

    ModInt operator-() const { return ModInt(-x); }

    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

    bool operator==(const ModInt &p) const { return x == p.x; }

    bool operator!=(const ModInt &p) const { return x != p.x; }

    ModInt inverse() const
    {
        long long a = x, b = mod, u = 1, v = 0, t;
        while (b > 0)
        {
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }

    ModInt pow(int64_t n) const
    {
        ModInt ret(1), mul(x);
        while (n > 0)
        {
            if (n & 1)
                ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

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

    friend istream &operator>>(istream &is, ModInt &a)
    {
        int64_t t;
        is >> t;
        a = ModInt<mod>(t);
        return (is);
    }

    static long long get_mod() { return mod; }
    static void factorialInit()
    {
        factorialMemo[0] = 1;
        for (ll i = 0; i < MAX_N - 1; i++)
        {
            factorialMemo[i + 1] = ModInt<mod>(factorialMemo[i] * (i + 1)).x;
        }
        initFinished = true;
    }
    static ModInt factorial(ll n)
    {
        if (!initFinished)
        {
            factorialInit();
        }
        return factorialMemo[n];
    }

    static ModInt Combination(ll n, ll k)
    {
        if (n < k)
            return 0;
        return factorial(n) / (factorial(n - k) * factorial(k));
    }
};
using mint = ModInt<998244353>;
template <typename Set>
struct Monoid
{
    using Op = function<Set(Set, Set)>;
    const Op f;
    const Set e;
    Monoid(const Op F, const Set E) : f(F), e(E)
    {
    }
};
template <typename Set>
struct SegmentTree
{
    using Op = function<Set(Set, Set)>;
    Monoid<Set> M;
    Set e;
    int size; //一番下以外の区間たち全部の数
    vector<Set> seg;
    SegmentTree(int n, const Monoid<Set> &M) : M(M)
    {
        size = 1;
        while (size < n)
        {
            size <<= 1;
        }
        e = M.e;
        seg.assign(2 * size, e);
    }
    void set(int k, const Set &x)
    {
        seg[k + size] = x;
    }
    void build()
    {
        for (int k = size - 1; k > 0; k--)
        {
            seg[k] = M.f(seg[2 * k + 0], seg[2 * k + 1]);
        }
    }
    void update(int k, const Set &x)
    {
        k += size;
        seg[k] = x;
        while (k >>= 1)
        {
            seg[k] = M.f(seg[2 * k + 0], seg[2 * k + 1]);
        }
    }
    Set query(int a, int b) //区間[a,b)に対して演算したやつを返す
    {
        Set L = e, R = e;
        for (a += size, b += size; a < b; a >>= 1, b >>= 1) //ループ一回ごとにa,bは親に向かう
        {
            if (a & 1) //a%2==1なら
            {
                L = M.f(L, seg[a++]);
            }
            if (b & 1)
            {
                R = M.f(seg[--b], R);
            }
        }
        return M.f(L, R);
    }
};
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int N, K;
    cin >> N >> K;
    vint L(K), R(K);
    for (size_t i = 0; i < K; i++)
    {
        cin >> L[i] >> R[i];
    }
    Monoid<mint> M([](mint a,mint b){return a+b;},0);
    SegmentTree<mint> seg(N+10,M);
    vector<mint> dp(N+10);
    dp[1] = 1;
    seg.update(1,1);
    
    
    for (int i = 2; i <= N; i++)
    {
        for (size_t j = 0; j < K; j++)
        {
            if(max(1,i-R[j]) < i-L[j]+1)
            dp[i] += seg.query(max(1,i-R[j]),i-L[j]+1);
        }
        //acc[i+1] = acc[i]+dp[i];
        seg.update(i,dp[i]);
    }
    cout<<dp[N];
    return 0;
}

Measured memory_bytes: 24560