#include <bits/stdc++.h>

#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

#define rep(i,n) for (int i = 0; i < (n); ++i)
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
#define all(x) (x).begin(), (x).end()
using namespace std;
using namespace atcoder;
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;

#define MOD 998244353
struct mint {
	int i;
	mint() : i(0) {}
	mint(int x) {
		i = int(x % MOD);
		if (i < 0) i += MOD;
	}
	template<class T> mint(T x) {
		i = int(x % MOD);
		if (i < 0) i += MOD;
	}
	mint operator+(const mint x) const {return i + x.i;}
	mint operator-(const mint x) const {return i - x.i;}
	mint operator*(const mint x) const {return (long long)i * x.i;}
	mint operator/(const mint x) const {return (long long)i * x.pow(MOD - 2).i;}
	mint inv() {return pow(MOD - 2);}
	template<class T> mint pow(T p) const {
		long long r = 1;
		long long t = i;
		for(; p > 0; p >>= 1) {
			if (p & 1) r = r * t % MOD;
			t = t * t % MOD;
		}
		return r;
	}
	template<class T1, class T2> static mint pow(T1 a, T2 b) {
		long long r = 1;
		long long t = (long long)(a % MOD);
		for(; b > 0; b >>= 1) {
			if (b & 1) r = r * t % MOD;
			t = t * t % MOD;
		}
		return r;
	}
	mint& operator+=(const mint x) {
		i = (i + x.i) % MOD;
		return *this;
	}
	mint& operator-=(const mint x) {
		i = i - x.i;
		if (i < 0) i += MOD;
		return *this;
	}
	mint& operator*=(const mint x) {
		i = (int)((long long)i * x.i % MOD);
		return *this;
	}
	mint& operator/=(const mint x) {
		i = (long long)i * x.pow(MOD - 2).i % MOD;
		return *this;
	}
};

std::ostream& operator<<(std::ostream& os, const mint& m) {
	return os << m.i;
}

mint op(mint a, mint b) {return a + b;}
mint e() {return 0;}
mint mapping(mint f, mint x) {return f + x;}
mint composition(mint f, mint g) {return f + g;}
mint id() {return 0;}

int main() {
    int n, k;
    cin >> n >> k;
    lazy_segtree<mint, op, e, mint, mapping, composition, id> a(n);
    a.set(0, 1);
    VI l(k), r(k);
    rep(i, k) {
        cin >> l[i] >> r[i];
        r[i]++;
    }
    rep(i, n) {
        rep(ki, k) {
            int tl = i + l[ki], tr = min(n, i + r[ki]);
            if (tl >= tr) continue;
            a.apply(tl, tr, a.get(i));
        }
    }
    cout << a.get(n-1) << endl;
}


Measured memory_bytes: 7188