#include <bits/stdc++.h>
// #include <boost/multiprecision/cpp_int.hpp>
using namespace std;

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define MIN(a) *std::min_element((a).begin(), (a).end())
#define MAX(a) *std::max_element((a).begin(), (a).end())
#define SUM(a) std::accumulate((a).begin(), (a).end(), 0LL)
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define RREP(i, n) for (int (i) = (n)-1; (i) >= 0; (i)--)
#define FOR(i, m, n) for (int (i) = (m); (i) < (n); i++)
#define FORR(i, m, n) for (int (i) = (n)-1; (i) >= (m); i--)
#define debug(x) std::cerr << #x << " = " << x << '\n'
// #define int long long

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using vl = std::vector<long long>;
using vvl = std::vector<std::vector<long long>>;
// using bint = boost::multiprecision::cpp_int;
// using rat = boost::rational<bint>;

constexpr int inf = (1 << 30) - 1;
constexpr long long INF = 1LL << 60;
constexpr double eps = 1e-9;

inline void ios_() {std::cin.tie(nullptr); std::ios::sync_with_stdio(false);}
template<typename T> inline T Div(const T& a, const T& b) {return (a + b - 1) / b;}
template<typename T> bool chmin(T& a, const T& b) {if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, const T& b) {if(a < b){a = b; return true;} return false;}

template<typename T>
inline void finish(const T& msg) {
    std::cout << msg << std::endl;
    std::exit(0);
}

template<typename T>
long long binarySearch(long long ng, long long ok, const T& fn) {
    while (std::abs(ok - ng) > 1) {
        long long mid = (ok + ng) / 2;
        if (fn(mid)) ok = mid;
        else ng = mid;
    }
    return ok;
}

struct ModInt {
    long long value;
    // static constexpr long long mod = 1e9+7;
    static constexpr long long mod = 998244353;

    constexpr ModInt(long long v = 0) : value(((v % mod) + mod) % mod) {}

    constexpr ModInt pow(long long n) const {
        long long x = value, res = 1;
        while (n > 0) {
            if (n & 1) {
                res = res * x % mod;
            }
            x = x * x % mod;
            n >>= 1;
        }
        return ModInt(res);
    }

    constexpr ModInt inverse() const {
        return pow(mod - 2);
    }

    constexpr ModInt operator-() const {
        return ModInt((mod - value) % mod);
    }

    constexpr ModInt& operator+=(const ModInt& a) {
        value += a.value;
        value %= mod;
        return *this;
    }

    constexpr ModInt& operator-=(const ModInt& a) {
        value += (-a).value;
        value %= mod;
        return *this;
    }

    constexpr ModInt& operator*=(const ModInt& a) {
        value *= a.value;
        value %= mod;
        return *this;
    }

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

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

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

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

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

    constexpr bool operator==(const ModInt& a) const {
        return value == a.value;
    }

    constexpr bool operator!=(const ModInt& a) const {
        return value != a.value;
    }

    friend std::istream& operator>>(std::istream& is, ModInt& a) {
        long long v;
        is >> v;
        a = v;
        return is;
    }

    friend std::ostream& operator<<(std::ostream& os, const ModInt& a) {
        os << a.value;
        return os;
    }

    static ModInt factorial(int n) {
        static std::vector<ModInt> fact(1 << 18);

        if (fact.size() <= n) fact.resize(n + 1);

        if (n < 0) return 0;
        if (n == 0) return 1;
        if (fact[n] != 0) return fact[n];

        return fact[n] = factorial(n - 1) * n;
    }

    static ModInt combin(int n, int k) {
        if (n < 0 || k < 0 || n < k) return 0;
        return factorial(n) / (factorial(k) * factorial(n - k));
    }
};

using mint = ModInt;

template<typename T> struct SegmentTree {
    int N;                  //要素数
    T idt;                  //単位元
    vector<T> node;         //ノード (1-indexed, node[0]=idt)
    function<T(T,T)> fn;    //二項演算

    //要素を引数のベクトルから受け取る
    SegmentTree(const vector<T>& v, T id, function<T(T,T)> f) : idt(id), fn(f) {
        N = 1 << calcRank(v.size());
        node.resize(2*N);
        
        for(int i=0; i<2*N; i++) {
            if(i >= N && i < N + v.size()) {    //最下層のノードに要素を格納
                node[i] = v[i - N];
            }else{
                node[i] = idt;
            }
        }

        build();
    }

    int calcRank(int n) {
        int res = 0;
        n--;
        while(n > 0) {
            res++;
            n /= 2;
        }
        return res;
    }

    void build() {
        for (int i=N-1; i>0; i--) {
            node[i] = fn(node[2*i], node[2*i + 1]);
        }
    }

    void update(int k, T value) {    //値の更新
        k += N;    //要素番号->ノード番号
        node[k] = value;

        while(k > 1) {
            k /= 2;
            node[k] = fn(node[2*k], node[2*k + 1]); //上に向かって値を更新する
        }
    }

    T query(int a, int b) {  //半開区間 [a,b) に対するクエリ
        return query(a, b, 1, 0, N);
    }

    T query(int a, int b, int k, int l, int r) { //計算用の内部関数
        if(r <= a || b <= l) {   //[a,b) と [l,r) が交差しない場合
            return idt;
        }
        if(a <= l && r <= b) {   //[l,r) が [a,b) に含まれる場合
            return node[k];
        }

        T vl = query(a, b, 2*k, l, (l+r)/2);    //左右に分けて再帰
        T vr = query(a, b, 2*k+1, (l+r)/2, r);

        return fn(vl, vr);
    }
};

template<typename T> struct LazySegmentTree : SegmentTree<T> {
    vector<T> lazy;
    function<T(T,T)> gn;
    function<T(T,int)> p;

    LazySegmentTree(const vector<T>& v,
                    T id,
                    function<T(T,T)> f,
                    function<T(T,T)> g,
                    function<T(T,int)> p) : SegmentTree<T>(v, id, f), gn(g), p(p) {
        lazy.resize(2*this->N, id);
    }

    void eval(int k, int len) { // 遅延配列のデータを適用
        if(lazy[k] == this->idt) return;
        if(k < this->N) {
            lazy[2*k] = gn(lazy[2*k], lazy[k]);
            lazy[2*k+1] = gn(lazy[2*k+1], lazy[k]); 
        }
        this->node[k] = gn(this->node[k], p(lazy[k], len));
        lazy[k] = this->idt;
    }

    T update(int a, int b, T value, int k, int l, int r) {
        eval(k, r - l);

        if(r <= a || b <= l) return this->node[k];
        if(a <= l && r <= b) {
            lazy[k] = gn(lazy[k], value);
            return gn(this->node[k], p(lazy[k], r - l));
        }

        T vl = update(a, b, value, k*2, l, (l+r)/2);
        T vr = update(a, b, value, 2*k+1, (l+r)/2, r);
        return this->node[k] = this->fn(vl, vr);
    }

    void update(int a, int b, T value) {    // 区間 [a,b) を更新
        update(a, b, value, 1, 0, this->N);
    }

    T query(int a, int b, int k, int l, int r) {
        eval(k, r - l);

        if(r <= a || b <= l) return this->idt;
        if(a <= l && r <= b) return this->node[k];

        T vl = query(a, b, 2*k, l, (l+r)/2);
        T vr = query(a, b, 2*k+1, (l+r)/2, r);

        return this->fn(vl, vr);
    }

    T query(int a, int b) {  //半開区間 [a,b) に対するクエリ
        return query(a, b, 1, 0, this->N);
    }
};

signed main() {
    ios_();
    int n, k;
    cin >> n >> k;

    vector<pair<int,int>> v(k);
    REP(i, k) cin >> v[i].first >> v[i].second;

    LazySegmentTree<mint> tree(
        vector<mint>(n),
        mint(0),
        [](mint a, mint b){return a + b;},
        [](mint a, mint b){return a + b;},
        [](mint a, int b){return a * mint(b);}
    );

    tree.update(0, 1, 1);

    REP(i, n){
        mint a = tree.query(i, i+1);
        REP(j, k){
            int l = v[j].first, r = v[j].second;
            tree.update(i + l, i + r + 1, a);
        }

    }


    cout << tree.query(n-1, n) << endl;


    return 0;
}


Measured memory_bytes: 12976