constexpr bool isDebugMode = false;
int testcase = 1;
#include <bits/stdc++.h>
// #include <intrin.h>

#if __has_include(<atcoder/all>)
    // #include <atcoder/all>
    // using namespace atcoder;
#endif
using namespace std;
typedef long long ll;
typedef pair<long long, long long> P;
struct edge{long long to,cost;};
const int inf = 1 << 27;
const long long INF = 1LL << 60;
const int COMBMAX = 1001001;
const long long MOD = 998244353;
const long long dy[] = {-1, 0, 0, 1};
const long long dx[] = {0, -1, 1, 0};
const string abc = "abcdefghijklmnopqrstuvwxyz";
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define eachdo(v, e) for (const auto &e : (v))
#define all(v) (v).begin(), (v).end()
#define lower_index(v, e) (long long)distance((v).begin(), lower_bound((v).begin(), (v).end(), e))
#define upper_index(v, e) (long long)distance((v).begin(), upper_bound((v).begin(), (v).end(), e))
long long mpow(long long a, long long n, long long mod = MOD){long long res = 1; while(n > 0){if(n & 1)res = res * a % mod; a = a * a % mod; n >>= 1;} return res;}
void pt(){cout << endl; return;}
template<class Head> void pt(Head&& head){cout << head; pt(); return;}
template<class Head, class... Tail> void pt(Head&& head, Tail&&... tail){cout << head << " "; pt(forward<Tail>(tail)...);}
void dpt(){if(!isDebugMode) return; cout << endl; return;}
template<class Head> void dpt(Head&& head){if(!isDebugMode) return; cout << head; pt(); return;}
template<class Head, class... Tail> void dpt(Head&& head, Tail&&... tail){if(!isDebugMode) return; cout << head << " "; pt(forward<Tail>(tail)...);}
template<class T> void enu(T v){rep(i, v.size()) cout << v[i] << " " ; cout << endl;}
template<class T> void enu2(T v){rep(i, v.size()){rep(j, v[i].size()) cout << v[i][j] << " " ; cout << endl;}}
template<class T> void debug(T v){if(!isDebugMode) return; rep(i, v.size()) cout << v[i] << " " ; cout << endl;}
template<class T> void debug2(T v){if(!isDebugMode) return; rep(i, v.size()){rep(j, v[i].size()) cout << v[i][j] << " " ; cout << endl;}}
template<class T1, class T2> inline bool chmin(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}
template<class T1, class T2> inline bool chmax(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}
template<class T1, class T2> long long recgcd(T1 a, T2 b){return a % b ? recgcd(b, a % b) : b;}
bool valid(long long H, long long W, long long h, long long w) { return 0 <= h && h < H && 0 <= w && w < W; }

void solve();

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    // cin >> testcase;
    while(testcase--) solve();
    return 0;
}

struct mint {
long long x;
    mint(long long x = 0):x((x % MOD + MOD) % MOD){}
    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) 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 pow(long long t) const {if (!t) return 1; mint a = pow(t >> 1); a *= a; if (t&1) a *= *this; return a;}
    mint inv() const {return pow(MOD - 2);}
    mint& operator /= (const mint a) {return (*this) *= a.inv();}
    mint operator / (const mint a) const {mint res(*this); return res /= a;}
};

class combination {
    public:
    vector<mint> fact, ifact;
    combination(int n):fact(n + 1), ifact(n + 1) {
        assert(n < MOD);
        fact[0] = 1;
        for(int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i;
        ifact[n] = fact[n].inv();
        for(int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i;
    }
    mint operator()(int n, int k) {
        if (k < 0 || k > n) return 0;
        if (COMBMAX < n){
            mint ret = 1;
            for(long long i = 1; i <= k; i++){
                ret *= (n - i + 1);
                ret /= i;
            }
            return ret;
        }
        return fact[n] * ifact[k] * ifact[n - k];
    }

    mint multi(long long n, long long sum, long long l, long long r){
        long long m = r - l + 1;
        long long t = sum - n * (l - 1);
        mint ans = 0;
        for(long long k = 0; k <= (t - n) / m; k++){
            long long sign = k % 2 == 0 ? 1 : -1;
            mint temp = this->operator() (n, k);
            temp *= this->operator() (n + (t - n - m * k - 1), t - n - m * k);
            temp *= sign;
            ans += temp;
        }
        return ans;
    }
} com(COMBMAX);

namespace atcoder {

namespace internal {

// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
    int x = 0;
    while ((1U << x) < (unsigned int)(n)) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
    unsigned long index;
    _BitScanForward(&index, n);
    return index;
#else
    return __builtin_ctz(n);
#endif
}

}  // namespace internal

}  // namespace atcoder


namespace atcoder {

template <class S, S (*op)(S, S), S (*e)()> struct segtree {
  public:
    segtree() : segtree(0) {}
    segtree(int n) : segtree(std::vector<S>(n, e())) {}
    segtree(const std::vector<S>& v) : _n(int(v.size())) {
        log = internal::ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        return d[p + size];
    }

    S prod(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        S sml = e(), smr = e();
        l += size;
        r += size;

        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }
        return op(sml, smr);
    }

    S all_prod() { return d[1]; }

    template <bool (*f)(S)> int max_right(int l) {
        return max_right(l, [](S x) { return f(x); });
    }
    template <class F> int max_right(int l, F f) {
        assert(0 <= l && l <= _n);
        assert(f(e()));
        if (l == _n) return _n;
        l += size;
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(op(sm, d[l]))) {
                while (l < size) {
                    l = (2 * l);
                    if (f(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*f)(S)> int min_left(int r) {
        return min_left(r, [](S x) { return f(x); });
    }
    template <class F> int min_left(int r, F f) {
        assert(0 <= r && r <= _n);
        assert(f(e()));
        if (r == 0) return 0;
        r += size;
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(op(d[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (f(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
};

}  // namespace atcoder

    using namespace atcoder;
mint op(mint a, mint b){return a + b;}
mint e(){return 0;}
void solve(){
    ll N, K; cin >> N >> K;
    vector<ll> l(K), r(K);
    rep(i, K){
        cin >> l[i] >> r[i];
    }
    vector<mint> d(N + 1, 0);
    d[1] = 1;
    segtree<mint, op, e> dp(d);
    for(ll i = 1; i <= N; i++){
        rep(j, K){
            if(i - l[j] > 0){
                dp.set(i, dp.get(i) + dp.prod(max(1LL, i - r[j]), i - l[j] + 1));
            }
        }
    }
    // rep(i, N + 1) pt(dp.get(i).x);
    pt(dp.get(N).x);
}

Measured memory_bytes: 24580