#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
vector<long long> coins;
long long dp[200005], n;
long long make(long long amount) {
  if (amount == n) return 1;
  if (amount > n) return 0;
  if (dp[amount] != -1) return dp[amount];
  long long ans = 0;
  for (long long i = 0; i < coins.size(); i++) {
    ans =
        ((ans % 998244353) + (make(amount + coins[i]) % 998244353)) % 998244353;
  }
  return dp[amount] = ans % 998244353;
}
int main() {
  long long m, x, y;
  scanf("%lld %lld", &n, &m);
  memset(dp, -1, sizeof(dp));
  ;
  for (long long i = 0; i < m; i++) {
    scanf("%lld %lld", &x, &y);
    for (long long j = x; j <= y; j++) coins.push_back(j);
  }
  cout << make(1);
  return 0;
}
