#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds;
using namespace std;
typedef tree<pair<int,int>,null_type,less<pair<int,int>>,rb_tree_tag,tree_order_statistics_node_update> oset;
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
  enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
	*this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
using ll = long long;
#define ar array 

const int nax = 1e6+5;
const int M = 998'244'353;
#define int ll
set<int> c;
ll dp[nax];

void test_case() {
	int n , x;
	cin >> n >> x;
	for(int i = 0 ; i < 2*x ; i++){
		int p;
		cin >> p;
		c.insert(p);
	}
	dp[1] = 1;
	for(int i = 2 ; i <= n ; i++){
		for(auto j : c){
			if(j <= i){
				dp[i] = (dp[i]%M+dp[i-j]%M)%M;
			}
		}
	}
	cout<<dp[n]%M;
}
 
int32_t main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int T = 1;
	//~ cin >> T;
	while(T--){
		test_case();
	}
}
