#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;

const ll INF = 1e18;
const ll MOD = 1e9 + 7;

template<typename T> T chmax(T& a, const T& b){return a = (a > b ? a : b);}
template<typename T> T chmin(T& a, const T& b){return a = (a < b ? a : b);}

#define DEBUG_MODE
#ifdef DEBUG_MODE
#define dump(x) cout << #x << " : " << x << " "
#define dumpL(x) cout << #x << " : " << x << '\n'
#define LINE cout << "line : " << __LINE__ << " "
#define LINEL cout << "line : " << __LINE__ << '\n'
#define dumpV(v) cout << #v << " : ["; for(auto& t : v) cout << t << ", "; cout<<"]" << " "
#define dumpVL(v) cout << #v << " : ["; for(auto& t : v) cout << t << ", "; cout<<"]" << endl
#define STOP assert(false)
#else
#define dump(x) 
#define dumpL(x) 
#define LINE 
#define LINEL 
#define dumpV(v) 
#define dumpVL(v) 
#define STOP assert(false)
#endif
#define mp make_pair
 
namespace std {
template<class S, class T>
ostream &operator <<(ostream& out, const pair<S, T>& a) {
    out << '(' << a.fi << ", " << a.se << ')';
    return out;
}
}

template <typename T, typename U> T pow_fast(T x, U n) {
    T ret = (T)1;
    while(n) {
        if(n & (U)1) ret *= x;
        x *= x;
        n >>= 1;
    }
    return ret;
}

template <typename ModType, ModType MOD> struct ModInt {
    ModType val;
    ModInt() : val(0) {}
    ModInt(ModType x) : val(x % MOD) {
        if(val < 0) val += MOD;
    };
    operator ModType() const { return val; }
    ModInt &operator+=(const ModInt &m) {
        val += m.val;
        if(val >= MOD) val -= MOD;
        return *this;
    }
    ModInt &operator-=(const ModInt &m) {
        val -= m.val;
        if(val < 0) val += MOD;
        return *this;
    }
    ModInt &operator*=(const ModInt &m) {
        (val *= m.val) %= MOD;
        return *this;
    }
    ModInt &operator/=(const ModInt &m) {
        *this *= m.inverse();
        return *this;
    }
    ModInt operator+(const ModInt &m) const { return ModInt(*this) += m; }
    ModInt operator-(const ModInt &m) const { return ModInt(*this) -= m; }
    ModInt operator*(const ModInt &m) const { return ModInt(*this) *= m; }
    ModInt operator/(const ModInt &m) const { return ModInt(*this) /= m; }
    ModInt inverse() const { return pow_fast(*this, MOD - 2); }
    ModInt pow(ModType n) const {return pow_fast(*this, n); }

    friend std::ostream &operator<<(std::ostream &os, const ModInt &rhs) {
        os << rhs.val;
        return os;
    }
    friend std::istream &operator>>(std::istream &is, ModInt &rhs) {
        ModType value;
        is >> value;
        rhs = ModInt(value);
        return is;
    }
};


using ull = unsigned long long;


constexpr ll initVal = 0LL;     //TODO: fix type and value
constexpr ll initLazy = 0LL;    //TODO: fix type and value
template <typename T>
struct Node {
    T val;
    T lazy;
    ull l, r;
    Node<T>* l_node = nullptr;
    Node<T>* r_node = nullptr;
    Node(ull l, ull r, const T& val = initVal) : l(l), r(r), val(val), lazy(initLazy) {}
    T getVal() {
        return val + lazy * T(r - l); //TODO: fix
    }
    T f1(const T& a, const T& b) {
        return a+b;               //TODO: fix
    }
    T f2(const T& a, const T& b) {
        return a+b;                       //TODO: fix
    }
    void push() {
        if(r - l > 1) {
            auto m = (l+r)/2;
            {
                if(l_node == nullptr) l_node = new Node(l, m);
                if(lazy != initLazy) l_node->lazy = f2(l_node->lazy, this->lazy);
            }
            {
                if(r_node == nullptr) r_node = new Node(m, r);
                if(lazy != initLazy) r_node->lazy = f2(r_node->lazy, this->lazy); 
            }
        }
        val = getVal();
        lazy = initLazy;
    }
    void fix() {
        if(r - l == 1) return;
        val = f1(l_node->getVal(), r_node->getVal());
    }
    T query(ull qL, ull qR) {
        if(qR <= l || r <= qL) return initVal;
        if(qL <= l && r <= qR) return getVal();
        if(r - l == 1)  return getVal();

        push();
        T l_val = l_node->query(qL, qR), r_val = r_node->query(qL, qR);
        return f1(l_val, r_val);
    }
    void update(ull uL, ull uR, const T& uVal) {
        if(uR <= l || r <= uL) return;
        if(uL <= l && r <= uR) lazy = f2(lazy, uVal);
        else {
            push();
            l_node->update(uL, uR, uVal);
            r_node->update(uL, uR, uVal);
            fix();
        }
    }
};

template <typename T>
struct DynamicLazySegTree {
    Node<T> root;
    DynamicLazySegTree(ull l, ull r, const T& val) : root(l, r, val) {}
    T query(ull l, ull r) {
        return root.query(l, r);
    }
    void update(ull l, ull r, const T& val) {
        root.update(l, r, val);
    }
};



int main(){
    using mint = ModInt<ll, 998244353LL>;
    int n, k;
    cin >> n >> k;
    using T = tuple<int, int>;
    vector<T> v;
    rep(i, k) {
        int l, r;
        cin >> l >> r;
        v.emplace_back(l, r);
    }     
    sort(all(v));
    DynamicLazySegTree<mint> seg(0, n*2+10, 0);
    seg.update(1, 2, 1);

    REP(i, 1, n) {
        auto tmp = seg.query(i, i+1);
        for(auto&& t: v) {
            auto [l, r] = t;
            r++;
            // dump(l); dump(r);dump(i+l);dump(i+r);dumpL(tmp);
            seg.update(i+l, i+r, tmp);
        }
    //     rep(j, n+1) cerr << " " << seg.query(j, j+1);
    //     cout << '\n';
    }
    cout << seg.query(n, n+1) << '\n';
    return 0;
}

Measured memory_bytes: 53536