#include <iostream>
#include <iomanip>
#include <vector>
#include <utility>
#include <map>
#include <algorithm>
#include <queue>
#include <cmath>
#include <numeric>
#include <set>

using namespace std;
struct aaa{aaa(){cin.tie(nullptr); ios::sync_with_stdio(false); cout<<fixed<<setprecision(20);};}aaa;
template <class T>ostream &operator<<(ostream &o,const vector<T>&v){o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}
#define debug(v) {cerr<<"\033[1;36m[debug]\033[m "<<#v<<" : "<<v<<endl;}

using int64 = long long;

const int MOD = 998244353;
class mint {
    using int64 = long long;
private:
    int64 x;
public:
    mint(const int64 x1=0) { x = x1%MOD; };

    mint& operator++(int n) { x+=1; return *this; };
    mint& operator--(int n) { x-=1; return *this; };
    mint& operator=(int64 n) { x=n%MOD; return *this; };
    mint& operator--() {x-=1; return *this; };
    mint& operator+=(const mint a) { if ( (x+=a.x) >= MOD) x-=MOD; return *this; }
    mint& operator-=(const mint a) { if ( (x+= MOD-a.x) >= MOD) x-= MOD; return *this; }
    mint& operator*=(const mint a) { (x*=a.x) %= MOD; return *this; }
    mint& operator/=(const mint a) { return (*this) *= a.inv();}
    mint operator+(const mint a) const { mint res(*this); return res+=a; }
    mint operator-(const mint a) const { mint res(*this); return res-=a; }
    mint operator*(const mint a) const { mint res(*this); return res*=a; }
    mint operator/(const mint a) const { mint res(*this); return res/=a; }
    mint inv() const { return pow(MOD-2);}
    friend ostream& operator<<(ostream &os, const mint a) noexcept { return os << a.x; }
    constexpr bool operator == (const mint& r) const noexcept { return this->x == r.x; }
    constexpr bool operator != (const mint& r) const noexcept { return this->x != r.x; }
    mint pow(long long t) const {
        if (!t) return mint(1);
        mint a = pow(t>>1);
        a*=a;
        if(t&1) a*= *this;
        return a;
    }
};

template< typename Monoid, typename OperatorMonoid = Monoid >
struct LazySegmentTree {
    using F = function< Monoid(Monoid, Monoid) >;
    using G = function< Monoid(Monoid, OperatorMonoid) >;
    using H = function< OperatorMonoid(OperatorMonoid, OperatorMonoid) >;

    int sz, height;
    vector< Monoid > data;
    vector< OperatorMonoid > lazy;
    const F f;
    const G g;
    const H h;
    const Monoid M1;
    const OperatorMonoid OM0;


    LazySegmentTree(int n, const F f, const G g, const H h,
                    const Monoid &M1, const OperatorMonoid OM0)
        : f(f), g(g), h(h), M1(M1), OM0(OM0) {
        sz = 1;
        height = 0;
        while(sz < n) sz <<= 1, height++;
        data.assign(2 * sz, M1);
        lazy.assign(2 * sz, OM0);
    }

    void set(int k, const Monoid &x) {
        data[k + sz] = x;
    }

    void build() {
        for(int k = sz - 1; k > 0; k--) {
            data[k] = f(data[2 * k + 0], data[2 * k + 1]);
        }
    }

    inline void propagate(int k) {
        if(lazy[k] != OM0) {
            lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]);
            lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]);
            data[k] = reflect(k);
            lazy[k] = OM0;
        }
    }

    inline Monoid reflect(int k) {
        return lazy[k] == OM0 ? data[k] : g(data[k], lazy[k]);
    }

    inline void recalc(int k) {
        while(k >>= 1) data[k] = f(reflect(2 * k + 0), reflect(2 * k + 1));
    }

    inline void thrust(int k) {
        for(int i = height; i > 0; i--) propagate(k >> i);
    }

    void update(int a, int b, const OperatorMonoid &x) {
        thrust(a += sz);
        thrust(b += sz - 1);
        for(int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
            if(l & 1) lazy[l] = h(lazy[l], x), ++l;
            if(r & 1) --r, lazy[r] = h(lazy[r], x);
        }
        recalc(a);
        recalc(b);
    }

    Monoid query(int a, int b) {
        thrust(a += sz);
        thrust(b += sz - 1);
        Monoid L = M1, R = M1;
        for(int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
            if(l & 1) L = f(L, reflect(l++));
            if(r & 1) R = f(reflect(--r), R);
        }
        return f(L, R);
    }

    Monoid operator[](const int &k) {
        return query(k, k + 1);
    }

    template< typename C >
    int find_subtree(int a, const C &check, Monoid &M, bool type) {
        while(a < sz) {
            propagate(a);
            Monoid nxt = type ? f(reflect(2 * a + type), M) : f(M, reflect(2 * a + type));
            if(check(nxt)) a = 2 * a + type;
            else M = nxt, a = 2 * a + 1 - type;
        }
        return a - sz;
    }

    template< typename C >
    int find_first(int a, const C &check) {
        Monoid L = M1;
        if(a <= 0) {
            if(check(f(L, reflect(1)))) return find_subtree(1, check, L, false);
            return -1;
        }
        thrust(a + sz);
        int b = sz;
        for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
            if(a & 1) {
                Monoid nxt = f(L, reflect(a));
                if(check(nxt)) return find_subtree(a, check, L, false);
                L = nxt;
                ++a;
            }
        }
        return -1;
    }


    template< typename C >
    int find_last(int b, const C &check) {
        Monoid R = M1;
        if(b >= sz) {
            if(check(f(reflect(1), R))) return find_subtree(1, check, R, true);
            return -1;
        }
        thrust(b + sz - 1);
        int a = sz;
        for(b += sz; a < b; a >>= 1, b >>= 1) {
            if(b & 1) {
                Monoid nxt = f(reflect(--b), R);
                if(check(nxt)) return find_subtree(b, check, R, true);
                R = nxt;
            }
        }
        return -1;
    }
};


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

    const auto add = [](mint a, mint b){return a+b;};
    LazySegmentTree<mint> seg(n, add, add, add, 0, 0);
    seg.set(0, 1);
    vector<pair<int,int>> lr;
    for (int i=0; i<k; i++) {
        int l,r;
        cin >> l >> r;
        lr.emplace_back(l,r);
    }

    for (int i=0; i<n; i++) {
        for (int j=0; j<k; j++) {
            auto[l, r] = lr[j];
            if (i+l >= n) continue;
            seg.update(i+l, min(n+1, i+r+1), seg.query(i, i+1));
        }
    }

//    for (int i=0; i<n; i++) {
//        cerr<<seg.query(i,i+1)<<" ";
//    }cerr<<endl;

    cout << seg.query(n-1, n) << endl;
}
/*
 * 221823067
 * 221823067
 */

Measured memory_bytes: 10996