#include <bits/stdc++.h>
  
using namespace std;
  
template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
  
#define pb push_back
#define mp make_pair
#define cotu cout
#define itn int
#define Red ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define F first
#define S second
#define sz(x) (int)x.size()
#define all(x) (x).begin(), (x).end()
#define rep(i, n) for(int i = 0; i < n; ++i)
#define repr(i,n) for(int i = n - 1; i >= 0; --i)
#define Rep(i, a, n) for(int i = (a); i <=(n); ++i)
#define repst(i, n) for(auto it = n.begin(); it != n.end(); ++it)
#define Repr(i, a, n) for(int i = (n); i >= (a); --i)
#define setp(x) fixed << setprecision(x)
#define ordered_set tree<int , null_type,less<int >, rb_tree_tag,tree_order_statistics_node_update> 
 
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds; 
  
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
  
const int inf = int(1e9);
const ll INF = ll(1e16);
const int mod = 998244353;
const int N = 1e6 + 555; // TL MB
const double PI = acos(-1.0);
void mul(ll &x, ll y){
	x *= y;
	if(x >= mod) x %= mod;
} 
ll bp(ll a, ll n){
	ll r = 1;
	while(n){
		if(n & 1) mul(r, a);
		mul(a, a);
		n >>= 1;
	}
	return r; 
}
template<typename T_vector> // neal
void output_vector(const T_vector &v, bool add_one = false, int start = -1, int end = -1) {
    if (start < 0) start = 0;
    if (end < 0) end = int(v.size());
 
    for (int i = start; i < end; i++)
        cout << v[i] + (add_one ? 1 : 0) << (i < end - 1 ? ' ' : '\n');
}
int get(char c){
	if(c >= 'A') c = tolower(c);
	return c;
}
ll dp[N];
vector<int> vals;
int rec(int n){
	if(n < 1) return 0;
	if(n == 1) return 1;
	if(~dp[n]) return dp[n];
	dp[n] = 0;
	for(int x : vals) {
		if(n - x >= 1) {
			dp[n] += rec(n - x);
			dp[n] %= mod;
		}
		else break;
	}
	return dp[n];
}
void solve()
{ 
	int n, k;
	cin >> n >> k;
	rep(i, n + 1) dp[i] = -1;
	rep(i, k)
	{
		int l, r;
		cin >> l >> r;
		Rep(j, l, r) vals.pb(j);
	}
	sort(all(vals));
	cout << rec(n);	
}
	


int main()
{
	// freopen("input.txt", "r", stdin);
	// freopen("output.txt", "w", stdout);
    // Red;
  	int T = 1;
  	// cin >> T;
  	for(int i = 1; i <= T; ++i){
  		solve();
  	}
  	return 0;

}