#pragma region Macros
#pragma GCC optimize("O3")
#pragma GCC target("avx2,avx")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define rep2(i, a, b) for(ll i = a; i <= b; ++i)
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define rep3(i, a, b) for(ll i = a; i >= b; --i)
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vll vector<ll>
#define vpi vector<pii>
#define vpll vector<pll>
#define overload2(_1, _2, name, ...) name
#define vec(type, name, ...) vector<type> name(__VA_ARGS__)
#define VEC(type, name, size)                                                                                                                                  \
    vector<type> name(size);                                                                                                                                   \
    IN(name)
#define vv(type, name, h, ...) vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define VV(type, name, h, w)                                                                                                                                   \
    vector<vector<type>> name(h, vector<type>(w));                                                                                                             \
    IN(name)
#define vvv(type, name, h, w, ...) vector<vector<vector<type>>> name(h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))
#define vvvv(type, name, a, b, c, ...)                                                                                                                         \
    vector<vector<vector<vector<type>>>> name(a, vector<vector<vector<type>>>(b, vector<vector<type>>(c, vector<type>(__VA_ARGS__))))
#define fi first
#define se second
#define all(c) begin(c), end(c)
#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))
using namespace std;
string YES[2] = {"NO", "YES"};
string Yes[2] = {"No", "Yes"};
string yes[2] = {"no", "yes"};
template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
#define si(c) (int)(c).size()
#define INT(...)                                                                                                                                               \
    int __VA_ARGS__;                                                                                                                                           \
    IN(__VA_ARGS__)
#define LL(...)                                                                                                                                                \
    ll __VA_ARGS__;                                                                                                                                            \
    IN(__VA_ARGS__)
#define STR(...)                                                                                                                                               \
    string __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
#define CHR(...)                                                                                                                                               \
    char __VA_ARGS__;                                                                                                                                          \
    IN(__VA_ARGS__)
#define DBL(...)                                                                                                                                               \
    double __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
int scan() { return getchar(); }
void scan(int &a) { cin >> a; }
void scan(long long &a) { cin >> a; }
void scan(char &a) { cin >> a; }
void scan(double &a) { cin >> a; }
void scan(string &a) { cin >> a; }
template <class T, class S> void scan(pair<T, S> &p) { scan(p.first), scan(p.second); }
template <class T> void scan(vector<T> &);
template <class T> void scan(vector<T> &a) {
    for(auto &i : a) scan(i);
}
template <class T> void scan(T &a) { cin >> a; }
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &... tail) {
    scan(head);
    IN(tail...);
}
template <class T, class S> inline bool chmax(T &a, S b) {
    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T, class S> inline bool chmin(T &a, S b) {
    if(a > b) {
        a = b;
        return 1;
    }
    return 0;
}
vi iota(int n) {
    vi a(n);
    iota(all(a), 0);
    return a;
}
template <typename T> vi iota(vector<T> &a, bool greater = false) {
    vi res(a.size());
    iota(all(res), 0);
    sort(all(res), [&](int i, int j) {
        if(greater) return a[i] > a[j];
        return a[i] < a[j];
    });
    return res;
}
#define UNIQUE(x) sort(all(x)), x.erase(unique(all(x)), x.end())
vector<pll> factor(ll x) {
    vector<pll> ans;
    for(ll i = 2; i * i <= x; i++)
        if(x % i == 0) {
            ans.push_back({i, 1});
            while((x /= i) % i == 0) ans.back().second++;
        }
    if(x != 1) ans.push_back({x, 1});
    return ans;
}
template <class T> vector<T> divisor(T x) {
    vector<T> ans;
    for(T i = 1; i * i <= x; i++)
        if(x % i == 0) {
            ans.pb(i);
            if(i * i != x) ans.pb(x / i);
        }
    return ans;
}
template <typename T> void zip(vector<T> &x) {
    vector<T> y = x;
    sort(all(y));
    for(int i = 0; i < x.size(); ++i) { x[i] = lb(y, x[i]); }
}
int popcount(ll x) { return __builtin_popcountll(x); }
struct Setup_io {
    Setup_io() {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        cout << fixed << setprecision(15);
    }
} setup_io;
int in() {
    int x;
    cin >> x;
    return x;
}
ll lin() {
    unsigned long long x;
    cin >> x;
    return x;
}

template <typename T> struct edge {
    int from, to;
    T cost;
    int id;
    edge(int to, T cost) : from(-1), to(to), cost(cost) {}
    edge(int from, int to, T cost) : from(from), to(to), cost(cost) {}
    edge(int from, int to, T cost, int id) : from(from), to(to), cost(cost), id(id) {}
    edge &operator=(const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
};
template <typename T> using Edges = vector<edge<T>>;

using Tree = vector<vector<int>>;
using Graph = vector<vector<int>>;
template <class T> using Wgraph = vector<vector<edge<T>>>;
Graph getG(int n, int m = -1, bool directed = false, int margin = 1) {
    Tree res(n);
    if(m == -1) m = n - 1;
    while(m--) {
        int a, b;
        cin >> a >> b;
        a -= margin, b -= margin;
        res[a].emplace_back(b);
        if(!directed) res[b].emplace_back(a);
    }
    return move(res);
}
template <class T> Wgraph<T> getWg(int n, int m = -1, bool directed = false, int margin = 1) {
    Wgraph<T> res(n);
    if(m == -1) m = n - 1;
    while(m--) {
        int a, b;
        T c;
        cin >> a >> b >> c;
        a -= margin, b -= margin;
        res[a].emplace_back(b, c);
        if(!directed) res[b].emplace_back(a, c);
    }
    return move(res);
}

#define i128 __int128_t
#define ull unsigned long long int
#define TEST                                                                                                                                                   \
    INT(testcases);                                                                                                                                            \
    while(testcases--)
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
    for(auto &e : v) cout << e << " ";
    cout << endl;
    return os;
}
template <class T, class S> ostream &operator<<(ostream &os, const pair<T, S> &p) {
    cout << "(" << p.fi << ", " << p.se << ")";
    return os;
}
template <class S, class T> string to_string(pair<S, T> p) { return "(" + to_string(p.first) + "," + to_string(p.second) + ")"; }
template <class A> string to_string(A v) {
    if(v.empty()) return "{}";
    string ret = "{";
    for(auto &x : v) ret += to_string(x) + ",";
    ret.back() = '}';
    return ret;
}

void dump() { cerr << endl; }
template <class Head, class... Tail> void dump(Head head, Tail... tail) {
    cerr << to_string(head) << " ";
    dump(tail...);
}
#define endl '\n'
#ifdef _LOCAL
#undef endl
#define debug(x)                                                                                                                                               \
    cout << #x << ": ";                                                                                                                                        \
    dump(x)
#else
#define debug(x)
#endif
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

// int rnd(int n) { return uniform_int_distribution<int>(0, n - 1)(rng); }
// ll rndll(ll n) { return uniform_int_distribution<ll>(0, n - 1)(rng); }

template <typename T> static constexpr T inf = numeric_limits<T>::max() / 2;
#pragma endregion

namespace modular {
constexpr ll MOD = 998244353;
const int MAXN = 1100000;
template <ll Modulus> class modint {
    using u64 = ll;

  public:
    u64 a;

    constexpr modint(const u64 x = 0) noexcept : a(((x % Modulus) + Modulus) % Modulus) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr modint operator+(const modint rhs) const noexcept { return modint(*this) += rhs; }
    constexpr modint operator-(const modint rhs) const noexcept { return modint(*this) -= rhs; }
    constexpr modint operator*(const modint rhs) const noexcept { return modint(*this) *= rhs; }
    template <typename T> constexpr modint operator^(T rhs) const noexcept { return modint(*this) ^= rhs; }
    constexpr modint operator-() const noexcept { return modint() - *this; }
    constexpr modint &operator+=(const modint rhs) noexcept {
        a += rhs.a;
        if(a >= Modulus) { a -= Modulus; }
        return *this;
    }
    constexpr modint &operator-=(const modint rhs) noexcept {
        if(a < rhs.a) { a += Modulus; }
        a -= rhs.a;
        return *this;
    }
    constexpr modint &operator*=(const modint rhs) noexcept {
        a = a * rhs.a % Modulus;
        return *this;
    }
    constexpr bool operator==(const modint rhs) const noexcept { return a == rhs.a; }
    template <typename T> constexpr modint &operator^=(T n) noexcept {
        modint<Modulus> res = 1;
        modint<Modulus> x = a;
        while(n) {
            if(n & 1) res *= x;
            x *= x;
            n >>= 1;
        }
        a = res.a;
        return *this;
    }
};
#define mint modint<MOD>
#define vmint vector<mint>
vmint Inv{0, 1}, Prd{1, 1}, Invprd{1, 1};
mint inv(int n) {
    if(n > MAXN) return mint(n) ^ (MOD - 2);
    if(Inv.size() > n)
        return Inv[n];
    else {
        for(int i = Inv.size(); i <= n; ++i) Inv.emplace_back(Inv[MOD % i] * (-MOD / i));
        return Inv[n];
    }
}
mint inv(mint x) { return inv(x.a); }
mint prd(int n) {
    if(Prd.size() > n)
        return Prd[n];
    else
        for(int i = Prd.size(); i <= n; ++i) Prd.emplace_back(Prd[i - 1] * i);
    return Prd[n];
}
mint invprd(int n) {
    if(Invprd.size() > n)
        return Invprd[n];
    else
        for(int i = Invprd.size(); i <= n; ++i) Invprd.emplace_back(Invprd[i - 1] * inv(i));
    return Invprd[n];
}
mint modpow(ll a, ll n) {
    mint x = a;
    return x ^= n;
}
mint operator/(mint l, mint r) { return l * inv(r); }
mint &operator/=(mint &l, mint r) { return l = l / r; }
mint C(int a, int b) {
    if(a < 0 || b < 0) return 0;
    if(a < b) return 0;
    return prd(a) * invprd(b) * invprd(a - b);
}
mint P(int a, int b) {
    if(a < 0 || b < 0) return 0;
    if(a < b) return 0;
    return prd(a) * invprd(a - b);
}
ostream &operator<<(ostream &os, mint a) {
    os << a.a;
    return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> a) {
    for(auto &e : a) os << e << " ";
    return os;
}
mint operator*(ll x, mint y) { return y * x; }
istream &operator>>(istream &is, mint &a) {
    ll x;
    is >> x;
    a = x;
    return is;
}
mint proot = 3;

void FMT(vmint &f, const bool is_inv = false) {
    const int n = f.size();
    const mint root = is_inv ? inv(proot) : proot;
    vmint g(n);
    for(int b = n >> 1; b > 0; b >>= 1) {
        mint a = root ^ ((MOD - 1) / (n / b)), p = 1;
        for(int i = 0; i < n; i += b << 1) {
            rep(j, b) {
                f[i + j + b] *= p;
                g[(i >> 1) + j] = f[i + j] + f[i + b + j];
                g[(n >> 1) + (i >> 1) + j] = f[i + j] - f[i + b + j];
            }
            p *= a;
        }
        swap(f, g);
    }
    if(is_inv) rep(i, n) f[i] *= inv(n);
}

vmint mul(vmint x, const vmint &y) {
    int n = x.size() + y.size() - 1;
    int s = 1;
    while(s < n) s <<= 1;
    x.resize(s);
    FMT(x);
    vmint z(s);
    rep(i, y.size()) z[i] = y[i];
    FMT(z);
    rep(i, s) x[i] *= z[i];
    FMT(x, true);
    x.resize(n);
    return x;
}

using Poly = vmint;
Poly operator-(Poly f) {
    for(auto &&e : f) e = -e;
    return f;
}
Poly &operator+=(Poly &l, const Poly &r) {
    l.resize(max(l.size(), r.size()));
    rep(i, r.size()) l[i] += r[i];
    return l;
}
Poly operator+(Poly l, const Poly &r) { return l += r; }
Poly &operator-=(Poly &l, const Poly &r) {
    l.resize(max(l.size(), r.size()));
    rep(i, r.size()) l[i] -= r[i];
    return l;
}
Poly operator-(Poly l, const Poly &r) { return l -= r; }
Poly &operator<<=(Poly &f, size_t n) { return f.insert(f.begin(), n, 0), f; }
Poly operator<<(Poly f, size_t n) { return f <<= n; }
Poly &operator>>=(Poly &f, size_t n) { return f.erase(f.begin(), f.begin() + min(f.size(), n)), f; }
Poly operator>>(Poly f, size_t n) { return f >>= n; }
Poly operator*(const Poly &l, const Poly &r) { return mul(l, r); }
Poly &operator*=(Poly &l, const Poly &r) { return l = l * r; }
Poly inv(const Poly &f) {
    Poly g{1 / f[0]};
    while(g.size() < f.size()) {
        Poly x(f.begin(), f.begin() + min(f.size(), g.size() << 1)), y = g;
        x.resize(g.size() << 1), FMT(x);
        y.resize(g.size() << 1), FMT(y);
        rep(i, x.size()) x[i] *= y[i];
        FMT(x, true);
        x >>= g.size();
        x.resize(g.size() << 1), FMT(x);
        rep(i, x.size()) x[i] *= -y[i];
        FMT(x, true);
        g.insert(g.end(), x.begin(), x.begin() + g.size());
    }
    return Poly{begin(g), begin(g) + f.size()};
}
Poly integ(const Poly &f) {
    Poly res(f.size() + 1);
    for(int i = 1; i < (int)res.size(); ++i) res[i] = f[i - 1] / i;
    return res;
}
Poly deriv(const Poly &f) {
    if(f.size() == 0) return Poly();
    Poly res(f.size() - 1);
    rep(i, res.size()) res[i] = f[i + 1] * (i + 1);
    return res;
}
Poly log(const Poly &f) {
    Poly g = integ(inv(f) * deriv(f));
    return Poly{g.begin(), g.begin() + f.size()};
}
Poly exp(const Poly &f) {
    Poly g{1};
    while(g.size() < f.size()) {
        Poly x(f.begin(), f.begin() + min(f.size(), g.size() * 2));
        x[0] += 1;
        g.resize(2 * g.size());
        x -= log(g);
        x *= {g.begin(), g.begin() + g.size() / 2};
        rep2(i, g.size() / 2, min<int>(x.size(), g.size()) - 1) g[i] = x[i];
    }
    return {g.begin(), g.begin() + f.size()};
}

} // namespace modular
using namespace modular;

template <typename T = long long> struct SegmentTree {
    using F = function<T(T, T)>;
#define clz(x) __builtin_clz(x)

    SegmentTree(int n, const F f, const T &unit) : f(f), unit(unit), sz(n - 1 ? 1 << (32 - clz(n - 1)) : 1) { seg.assign(2 * sz, unit); }

    SegmentTree(vector<T> &a, const F f, const T &unit) : f(f), sz((int)a.size() > 1 ? 1 << (32 - clz(a.size() - 1)) : 1), unit(unit) {
        int n0 = a.size();
        seg.assign(2 * sz, unit);
        for(int i = 0; i < n0; ++i) seg[i + sz] = a[i];
        for(int i = sz - 1; i > 0; --i) seg[i] = f(seg[i << 1], seg[(i << 1) | 1]);
    }
    const int sz;
    vector<T> seg;
    const F f;
    const T unit;

    void set(int k, T x) { seg[k + sz] = x; }

    void build() {
        for(int i = sz - 1; i > 0; --i) seg[i] = f(seg[i << 1], seg[(i << 1) | 1]);
    }

    T query(int l, int r) {
        l = max(0, l), r = max(0, r);
        T x = unit;
        for(int d = r - l; d >= 1; d = r - l) {
            int L = l | ((1U << 31) >> clz(d));
            int k = __builtin_ctz(L);
            x = f(x, seg[(sz | l) >> k]);
            l += L & (-L);
        }
        return x;
    }

    void update(int i, T x) {
        int k = i + sz;
        seg[k] = x;
        for(k = k >> 1; k > 0; k >>= 1) { seg[k] = f(seg[k << 1], seg[(k << 1) | 1]); }
    }

    void add(int i, T x) {
        int k = i + sz;
        seg[k] += x;
        for(k = k >> 1; k > 0; k >>= 1) { seg[k] = f(seg[k << 1], seg[(k << 1) | 1]); }
    }
    SegmentTree() = default;
    T operator[](int k) const { return seg[sz + k]; }
};

template <typename T> struct RMQ : SegmentTree<T> {
    RMQ(int n)
        : SegmentTree<T>(
              n, [](T i, T j) { return max(i, j); }, numeric_limits<T>::min()) {}
    RMQ(vector<T> &a)
        : SegmentTree<T>(
              a, [](T i, T j) { return max(i, j); }, numeric_limits<T>::min()) {}
};

template <typename T> struct RmQ : SegmentTree<T> {
    RmQ(int n)
        : SegmentTree<T>(
              n, [](T i, T j) { return min(i, j); }, numeric_limits<T>::max()) {}
    RmQ(vector<T> &a)
        : SegmentTree<T>(
              a, [](T i, T j) { return min(i, j); }, numeric_limits<T>::max()) {}
};

template <typename T> struct RAQ : SegmentTree<T> {
    RAQ(int n) : SegmentTree<T>(n, plus<T>(), 0) {}
    RAQ(vector<T> &a) : SegmentTree<T>(a, plus<T>(), 0) {}
};

main() {
    INT(n);
    INT(k);
    vi l(k), r(k);
    rep(i, k) cin >> l[i] >> r[i];
    SegmentTree<mint> seg(
        n + 1, [](mint x, mint y) { return x + y; }, 0);
    seg.update(0, 1);
    rep2(i, 1, n - 1) {
        rep(j, k) { seg.add(i, seg.query(i - r[j], i - l[j] + 1)); }
    }
    cout << seg[n - 1] << endl;
}

Measured memory_bytes: 7476