#include <bits/stdc++.h>
using namespace std;
long long power(long long x, long long y) {
  if (y == 0)
    return 1;
  else if (y % 2 == 0)
    return (power(x, y / 2) * power(x, y / 2)) % 998244353;
  else
    return ((x * power(x, y / 2)) % 998244353 * power(x, y / 2)) % 998244353;
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long modInverse(long long n, long long p) { return power(n, p - 2, p); }
long long fac[100000 + 1];
void pre(long long p) {
  fac[0] = 1;
  for (long long i = 1; i <= 100000; i++) fac[i] = (fac[i - 1] * i) % p;
}
long long nCrModPFermat(long long n, long long r, long long p) {
  if (r == 0) return 1;
  if (r > n) return 0;
  return (fac[n] * modInverse(fac[r], p) % p * modInverse(fac[n - r], p) % p) %
         p;
}
vector<long long> v;
long long dp[200000 + 5];
long long calc(long long x) {
  long long ans = 0;
  if (x <= 0) return 0;
  if (x == 1) return 1;
  if (dp[x] != -1) return dp[x];
  for (auto it : v) {
    ans = (ans + calc(x - it)) % 998244353;
  }
  return dp[x] = ans;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, i, j, l, r, k;
  cin >> n >> k;
  memset(dp, -1, sizeof(dp));
  for (i = 0; i < k; i++) {
    cin >> l >> r;
    for (j = l; j <= r; j++) v.push_back(j);
  }
  calc(n);
  cout << dp[n];
  cerr << (1000 * clock()) / CLOCKS_PER_SEC << "ms";
  return 0;
}
