#include <iostream>
#include <vector>
#include <numeric>
#include <algorithm>
#include <climits>

constexpr int SINT_MAX = std::numeric_limits<int>::max();
constexpr int SINT_MIN = std::numeric_limits<int>::min();

using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;

template<class T>
T choose(bool b, T t, T f)
{
    if (b) return t;
    else return f;    
}

const char *YesNo(bool b)
{
    return choose(b, "Yes", "No");
}

const char *YESNO(bool b)
{
    return choose(b, "YES", "NO");
}

template<class NumT>
NumT diffabs(NumT l, NumT r)
{
    if (l < r) return r-l;
    else return l-r;    
}

struct myinout_t {} io;

template<class T>
myinout_t &operator >>(myinout_t &my, T &i)
{
    cin >> i;
    return my;
}

myinout_t &operator >>(myinout_t &my, int &i)
{
    int r = scanf("%d", &i);
    if (r != 1) exit(EXIT_FAILURE);
    return my;
}

myinout_t &operator >>(myinout_t &my, ll &i)
{
    int r = scanf("%lld", &i);
    if (r != 1) exit(EXIT_FAILURE);
    return my;
}

template<class T>
myinout_t &operator <<(myinout_t &my, const T &i)
{
    cout << i;
    return my;
}

myinout_t &operator <<(myinout_t &my, int i)
{
    printf("%d", i);
    return my;
}

myinout_t &operator <<(myinout_t &my, ll i)
{
    printf("%lld", i);
    return my;
}

myinout_t &operator <<(myinout_t &my, double i)
{
    printf("%.20f", i);
    return my;
}

constexpr char BR = '\n';


///////////////////////////////////////////////////

constexpr int MOD = 998244353;

#include <algorithm>

#ifdef _MSC_VER
#include <intrin.h>
#endif

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

#include <cassert>
#include <iostream>
#include <vector>
namespace atcoder {

template <class S,
          S (*op)(S, S),
          S (*e)(),
          class F,
          S (*mapping)(F, S),
          F (*composition)(F, F),
          F (*id)()>
struct lazy_segtree {
  public:
    lazy_segtree() : lazy_segtree(0) {}
    lazy_segtree(int n) : lazy_segtree(std::vector<S>(n, e())) {}
    lazy_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());
        lz = std::vector<F>(size, id());
        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;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        return d[p];
    }

    S prod(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return e();

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push(r >> i);
        }

        S sml = e(), smr = e();
        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]; }

    void apply(int p, F f) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = mapping(f, d[p]);
        for (int i = 1; i <= log; i++) update(p >> i);
    }
    void apply(int l, int r, F f) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        {
            int l2 = l, r2 = r;
            while (l < r) {
                if (l & 1) all_apply(l++, f);
                if (r & 1) all_apply(--r, f);
                l >>= 1;
                r >>= 1;
            }
            l = l2;
            r = r2;
        }

        for (int i = 1; i <= log; i++) {
            if (((l >> i) << i) != l) update(l >> i);
            if (((r >> i) << i) != r) update((r - 1) >> i);
        }
    }

    template <bool (*g)(S)> int max_right(int l) {
        return max_right(l, [](S x) { return g(x); });
    }
    template <class G> int max_right(int l, G g) {
        assert(0 <= l && l <= _n);
        assert(g(e()));
        if (l == _n) return _n;
        l += size;
        for (int i = log; i >= 1; i--) push(l >> i);
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!g(op(sm, d[l]))) {
                while (l < size) {
                    push(l);
                    l = (2 * l);
                    if (g(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 (*g)(S)> int min_left(int r) {
        return min_left(r, [](S x) { return g(x); });
    }
    template <class G> int min_left(int r, G g) {
        assert(0 <= r && r <= _n);
        assert(g(e()));
        if (r == 0) return 0;
        r += size;
        for (int i = log; i >= 1; i--) push((r - 1) >> i);
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!g(op(d[r], sm))) {
                while (r < size) {
                    push(r);
                    r = (2 * r + 1);
                    if (g(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;
    std::vector<F> lz;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
    void all_apply(int k, F f) {
        d[k] = mapping(f, d[k]);
        if (k < size) lz[k] = composition(f, lz[k]);
    }
    void push(int k) {
        all_apply(2 * k, lz[k]);
        all_apply(2 * k + 1, lz[k]);
        lz[k] = id();
    }
};

}  // namespace atcoder

using namespace atcoder;

int op(int l, int r)
{
    return (l + r) % MOD;
}

int e()
{
    return 0;
}

int mapping(int l, int r)
{
    return (l + r) % MOD;
}

int composition(int l, int r)
{
    return (l + r) % MOD;
}

int id()
{
    return 0;
}

int main()
{
    int N, K;
    io >> N >> K;

    int L[10], R[10];
    for (int i = 0; i < K; i++)
    {
        io >> L[i] >> R[i];
        R[i]++;
    }
    
    lazy_segtree<int, op, e, int, mapping, composition, id> seg(N);
    seg.set(0, 1);

    for (int i = 0; i < N; i++)
    {
        int ai = seg.get(i);
        for (int k = 0; k < K; ++k)
        {
            if (i + L[k] < N)
            {
                seg.apply(i + L[k], min(i + R[k], N), ai);
            }
        }
    }
    
    io << seg.get(N-1) << BR;
}


Measured memory_bytes: 7244