#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using P = pair<ll, ll>;

const ll MOD = 998244353;
const ll INF = 1ll<<60;

#define FOR(i,a,b) for (ll i=(a);i<(ll)(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define DEBUG(x) ;

int dx[4]{0, 1, 0, -1};
int dy[4]{1, 0, -1, 0};

template<int mod> struct Fp {
    long long val;
	
    constexpr Fp(long long v = 0) noexcept : val(v % mod) {
        if (val < 0) val += mod;
    }
    constexpr int getmod() { return mod; }
    constexpr Fp operator - () const noexcept {
        return val ? mod - val : 0;
    }
    constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp& r) noexcept {
        val += r.val;
        if (val >= mod) val -= mod;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) val += mod;
        return *this;
    }
    constexpr Fp& operator *= (const Fp& r) noexcept {
        val = val * r.val % mod;
        return *this;
    }
    constexpr Fp& operator /= (const Fp& r) noexcept {
        long long a = r.val, b = mod, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        val = val * u % mod;
        if (val < 0) val += mod;
        return *this;
    }
    constexpr bool operator == (const Fp& r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp& r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<mod>& x) noexcept {
        return os << x.val;
    }
    friend constexpr Fp<mod> modpow(const Fp<mod> &a, long long n) noexcept {
        if (n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if (n & 1) t = t * a;
        return t;
    }
	friend constexpr Fp<mod> modfac(long long l, long long r) noexcept
	{
		auto res = Fp<mod>(1);
		for (Fp<mod> i = l; i < r; ++i) res *= i;
		return res;
	}
};
using mint = Fp<MOD>;


template <class T>
struct BIT
{
	int N;
	vector<T> bit[2];
	BIT(int n_) {init (n_);}
	void init(int n)
	{
		N = n + 1;
		bit[0].assign(N, 0);
		bit[1].assign(N, 0);
	}

	void add_sub(int p, int i, T x)
	{
		for (int j = i; j < N; j += (j & -j))
			(bit[p][j] += x) %= MOD;
	}

	T sum_sub(int p, int i)
	{
		T res{0};
		for (int j = i; j > 0; j -= (j & -j))
			(res += bit[p][j]) %= MOD;
		return res;
	}

	void add(int l, int r, T x) // [l, r)
	{
		add_sub(0, l, -x*(l-1));
		add_sub(0, r, x*(r-1));
		add_sub(1, l, x);
		add_sub(1, r, -x);
	}

	T sum(int i)
	{
		ll res = (sum_sub(1, i) * i) % MOD;
		return (res + sum_sub(0, i)) % MOD;
	}

	T query(int l, int r) // [l, r)
	{
		return (sum(r-1) - sum(l-1) + MOD) % MOD;
	}

	int lower_bound(T w)
	{
		if (w <= 0)
		{
			return 0;
		}
		else
		{
			int x = 0, r = 1;
			while (r < N) r = r << 1;
			for (int len = r; len > 0; len = len >> 1)
			{
				ll now = x + len;
				if (now < N && bit[now] < w)
				{
					w -= bit[now];
					x += len;
				}
			}
			return x + 1; // 1-indexed
		}
	}
};

int main(int argc, char **argv)
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	ll N, K; cin >> N >> K;
	vector<ll> L(K), R(K);
	REP(i, K) cin >> L[i] >> R[i], R[i]++;

	BIT<ll> bit(100000*2+10);
	bit.add(1, 2, 1);
	for (ll s = 1; s < N; ++s)
	{
		ll t = bit.query(s, s+1);
		DEBUG(t);
		REP(i, K)
		{
			bit.add(min(N+1, s+L[i]), min(N+1, s+R[i]), t);
		}
	}

	std::cout << bit.query(N, N+1) << std::endl;
	return 0;
}


Measured memory_bytes: 6372