// One Batch Two Batch Penny and Dime

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ll long long
#define hii cout << "hii" << endl
#define int long long
#define endl '\n'
#define all(s) s.begin(), s.end()
 
template <class T> ostream& operator << (ostream &os, const vector<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T> ostream& operator << (ostream &os, const set<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T, class S> ostream& operator << (ostream &os, const pair<T, S> &v) { os << v.first << ' ' << v.second; return os; }
template <class T, class S> ostream& operator << (ostream &os, const unordered_map<T, S> &v) { for (auto i : v) os << '(' << i.first << "=>" << i.second << ')' << ' '; return os; }
 
 
#ifndef ONLINE_JUDGE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
    template <class Arg1> void __f(const char* name, Arg1&& arg1) { cerr << name << " : " << arg1 << endl; }
    template <class Arg1, class... Args>
    void __f(const char* names, Arg1&& arg1, Args&&... args) {
        const char* sep = strchr(names + 1, ',');
        cerr.write(names, sep - names) << " : " << arg1 << "  ";
        __f(sep + 1, args...);
    }
#else
#define trace(...) 0
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define _CRT_SECURE_NO_WARNINGS
#endif // ifndef ONLINE_JUDGE

const int N = 5e5 + 5;
const int MAXN = 1e6 + 5;
const int M = 1e6 + 5;
const int mod = 998244353;
const int MOD = 998244353;
const int INF = 1e18 + 8;
const int LG = 21;

int arr[M];

class segtree
{
public:
	vector<int> v;
	int N;
 
	segtree(int n)
	{
		v.assign(4 * n + 5, 0);
		N = n;
	}
 
	void buildtree(int s, int e, int treenode)
	{
		if(s == e)
		{
			v[treenode] = 0;
			return;
		}
		int mid = s + e >> 1;
		buildtree(s, mid, 2 * treenode + 1);
		buildtree(mid + 1, e, 2 * treenode + 2);
		v[treenode] = v[2 * treenode + 1] + v[2 * treenode + 2];
	}
 
	void updatetree(int idx, int val, int s, int e, int treenode)
	{
		if(s == e)
		{
			v[treenode] = val;
			return;
		}
		int mid = s + e >> 1;
		if(idx <= mid)updatetree(idx, val, s, mid, 2 * treenode + 1);
		else updatetree(idx, val, mid + 1, e, 2 *treenode + 2);
		v[treenode] = v[2 * treenode + 1] + v[2 * treenode + 2];
	}
 
	int querytree(int l, int r, int s, int e, int treenode)
	{
		if(s >= l and e <= r)
	    {
	        return v[treenode];
	    }
	    if(s > r or l > e) return 0;
	    int mid = s + e >> 1;
	    int left = querytree(l, r,  s, mid, 2 * treenode + 1);
	    int right = querytree(l, r,  mid + 1, e, 2 * treenode + 2);
	    return left + right;
	}
 
	void update(int idx, int val)
	{
		updatetree(idx, val, 0, N - 1, 0);
	}
 
	int query(int l, int r)
	{	if(l > r) return 0;
		return querytree(l, r, 0, N - 1, 0);
	}
 
	void build()
	{
		buildtree(0, N - 1, 0);
	}
 
};


void solve()
{
	int n, k;
	cin >> n >> k;
	vector<pair<int, int>> v;
	for(int i = 0; i < k; i++)
	{
		int l, r;
		cin >> l >> r;
		v.push_back({l, r});
	}
	segtree stree(3 * N);
	stree.update(n, 1);
	for(int i = n - 1; i >= 1; i--)
	{
		int temp = 0;
		for(int j = 0; j < k; j++)
		{
			int s = i + v[j].first;
			int e = i + v[j].second;
			temp += stree.query(s, e);
			temp %= mod;
		}
		stree.update(i, temp);
	}
	cout << stree.query(1, 1) << endl;
}


 
int32_t main() 
{	
	ios_base:: sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	    int t = 1;
	    // cin >> t;
	while(t--)solve();
	return 0;
}

Measured memory_bytes: 50196