#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <numeric>
#include <utility>
#include <tuple>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<int, int>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

#include <functional>
template<typename T>
class SegmentTreeAllOne {
    using Func = function<T(T, T)>;

public:
    vector<T> data;
    int n;
    T init;
    Func update_func;
    SegmentTreeAllOne(int _n, T _init, Func up) {
        init = _init;
        update_func = up;
        for (n = 1; n < _n; n *= 2)
            ;
        data.resize(2 * n - 1, init);
    }
    void update(int l, int r, T val) {
        for (l += n - 1, r += n - 1; l < r; l = l / 2, r = (r - 1) / 2) {
            if (!(l & 1)) {
                data[l] = update_func(data[l], val);
            }
            if (!(r & 1)) {
                data[r - 1] = update_func(data[r - 1], val);
            }
        }
    }
    T query(int pos) {
        pos += n - 1;
        T res = data[pos];
        while (pos > 0) {
            pos = (pos - 1) / 2;
            res = update_func(res, data[pos]);
        }
        return res;
    }
};

template<ll MOD = 1000000007>
class ModInt {
    ll n;
    ModInt constexpr inverse() const {
        return ModInt::pow(*this, MOD - 2);
    }

public:
    ModInt()
        : n(0) {}
    ModInt(ll _n)
        : n(((_n % MOD) + MOD) % MOD) {}
    ModInt operator+=(const ModInt &m) {
        n += m.n;
        if (n >= MOD) n -= MOD;
        return *this;
    }
    ModInt operator-=(const ModInt &m) {
        n -= m.n;
        if (n < 0) n += MOD;
        return *this;
    }
    ModInt operator*=(const ModInt &m) {
        n *= m.n;
        if (n >= MOD) n %= MOD;
        return *this;
    }
    ModInt operator/=(const ModInt &m) {
        (*this) *= m.inverse();
        return *this;
    }
    friend ModInt operator+(ModInt t, const ModInt &m) {
        return t += m;
    }
    friend ModInt operator-(ModInt t, const ModInt &m) {
        return t -= m;
    }
    friend ModInt operator*(ModInt t, const ModInt &m) {
        return t *= m;
    }
    friend ModInt operator/(ModInt t, const ModInt &m) {
        return t /= m;
    }
    ModInt operator=(const ll l) {
        n = l % MOD;
        if (n < 0) n += MOD;
        return *this;
    }
    friend ostream &operator<<(ostream &out, const ModInt &m) {
        out << m.n;
        return out;
    }
    friend istream &operator>>(istream &in, ModInt &m) {
        ll l;
        in >> l;
        m = l;
        return in;
    }
    static constexpr ModInt pow(const ModInt x, ll p) {
        ModInt<MOD> ans = 1;
        for (ModInt<MOD> m = x; p > 0; p /= 2, m *= m) {
            if (p % 2) ans *= m;
        }
        return ans;
    }
};
using mint = ModInt<998244353>;
mint operator"" _m(unsigned long long m) {
    return mint(m);
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n, k;
    cin, n, k;
    vector<P> LR(k);
    REP(i, 0, k) {
        int l, r;
        cin, l, r;
        LR[i] = P(l, r);
    }
    sort(LR.begin(), LR.end());
    auto add = [&](mint a, mint b) {
        return a + b;
    };
    SegmentTreeAllOne<mint> seg(n, 0_m, add);
    seg.update(0, 1, 1);

    REP(i, 0, n) {
        mint s = seg.query(i);
        for (auto [l, r] : LR) {
            l = min(i + l, n);
            r = min(i + r, n);
            seg.update(l, r + 1, s);
        }
    }

    print(seg.query(n - 1));

    return 0;
}


Measured memory_bytes: 7428