#pragma region template 3.0
#define G3(_1, _2, _3, F, ...) F
#define G4(_1, _2, _3, _4, F, ...) F
#define G5(_1, _2, _3, _4, _5, F, ...) F
#define G6(_1, _2, _3, _4, _5, _6, F, ...) F
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <typename T>
using vec = vector<T>;
template <typename T>
using vec2 = vec<vec<T>>;
template <typename T>
using vec3 = vec<vec2<T>>;
template <typename T>
using vec4 = vec<vec3<T>>;
using vi = vec<ll>;
using vvi = vec2<ll>;
using ii = pair<ll, ll>;
using iii = tuple<ll, ll, ll>;
using vii = vec<ii>;
using vs = vec<string>;
using vb = vec<bool>;
template <typename T>
using pq = priority_queue<T, vector<T>, greater<T>>;
#define VEC1(T, n1) vec<T>(n1)
#define VEC2(T, n1, n2) vec2<T>(n1, VEC1(T, n2))
#define VEC3(T, n1, n2, n3) vec3<T>(n1, VEC2(T, n2, n3))
#define VEC4(T, n1, n2, n3, n4) vec4<T>(n1, VEC3(T, n2, n3, n4))
#define vec(...) G5(__VA_ARGS__, VEC4, VEC3, VEC2, VEC1)(__VA_ARGS__)
#define VEC1V(T, n1, v) vec<T>(n1, v)
#define VEC2V(T, n1, n2, v) vec2<T>(n1, VEC1V(T, n2, v))
#define VEC3V(T, n1, n2, n3, v) vec3<T>(n1, VEC2V(T, n2, n3, v))
#define VEC4V(T, n1, n2, n3, n4, v) vec4<T>(n1, VEC3V(T, n2, n3, n4, v))
#define vecv(...) G6(__VA_ARGS__, VEC4V, VEC3V, VEC2V, VEC1V)(__VA_ARGS__)
#define REP0(i, n) for (ll i = 0; i < (n); ++i)
#define REP(i, j, n) for (ll i = (j); i < (n); ++i)
#define rep(...) G3(__VA_ARGS__, REP, REP0)(__VA_ARGS__)
#define REP1(i, n) for (ll i = 1; i <= (n); ++i)
#define REPI(i, j, n) for (ll i = (j); i <= (n); ++i)
#define repi(...) G3(__VA_ARGS__, REPI, REP1)(__VA_ARGS__)
#define RREP0(i, n) for (ll i = (n)-1; i >= 0; --i)
#define RREP(i, j, n) for (ll i = (n)-1; i >= (j); --i)
#define rrep(...) G3(__VA_ARGS__, RREP, RREP0)(__VA_ARGS__)
#define RREP1(i, n) for (ll i = (n); i >= 1; --i)
#define RREPI(i, j, n) for (ll i = (n); i >= (j); --i)
#define rrepi(...) G3(__VA_ARGS__, RREPI, RREP1)(__VA_ARGS__)
#define each(i, a) for (auto &i : a)
#define ch(f, x, y) x = f((x), (y))
#define ALL(a) (a).begin(), (a).end()
#define SORT(a) sort(ALL(a))
#define RSORT(a) \
  SORT(a);       \
  reverse(ALL(a))
#define IN1(T, a) \
  T a;            \
  cin >> a;
#define IN2(T, a, b) \
  T a, b;            \
  cin >> a >> b;
#define IN3(T, a, b, c) \
  T a, b, c;            \
  cin >> a >> b >> c;
#define IN4(T, a, b, c, d) \
  T a, b, c, d;            \
  cin >> a >> b >> c >> d;
#define in(...) G5(__VA_ARGS__, IN4, IN3, IN2, IN1)(__VA_ARGS__)
#define ll(...) in(ll, __VA_ARGS__)
#define STR(...) in(string, __VA_ARGS__)
#define VIN1(T, a, n) \
  vec<T> a(n);        \
  each(i, a) cin >> i;
#define VIN2(T, a, b, n) \
  vec<T> a(n), b(n);     \
  rep(i, n) cin >> a[i] >> b[i];
#define VIN3(T, a, b, c, n) \
  vec<T> a(n), b(n), c(n);  \
  rep(i, n) cin >> a[i] >> b[i] >> c[i];
#define VIN4(T, a, b, c, d, n)   \
  vec<T> a(n), b(n), c(n), d(n); \
  rep(i, n) cin >> a[i] >> b[i] >> c[i] >> d[i];
#define vin(...) G6(__VA_ARGS__, VIN4, VIN3, VIN2, VIN1)(__VA_ARGS__)
#define vll(...) vin(ll, __VA_ARGS__)
#define vvll(a, n)       \
  vvi a = vec(ll, n, n); \
  rep(i, n) rep(j, n) cin >> a[i][j];
#define out(x) cout << (x) << endl;
#define fout(x) cout << fixed << setprecision(15) << (x) << endl;
#define DUMP1(a) cout << #a << " = " << (a) << endl;
#define DUMP2(a, b) \
  cout << #a << " = " << (a) << ' ' << #b << " = " << (b) << endl;
#define DUMP3(a, b, c)                                                 \
  cout << #a << " = " << (a) << ' ' << #b << " = " << (b) << ' ' << #c \
       << " = " << (c) << endl;
#define DUMP4(a, b, c, d)                                              \
  cout << #a << " = " << (a) << ' ' << #b << " = " << (b) << ' ' << #c \
       << " = " << (c) << ' ' << #d << " = " << (d) << endl;
#define DUMP5(a, b, c, d, e)                                              \
  cout << #a << " = " << (a) << ' ' << #b << " = " << (b) << ' ' << #c    \
       << " = " << (c) << ' ' << #d << " = " << (d) << ' ' << #e << " = " \
       << (e) << endl;
#define dump(...) \
  G5(__VA_ARGS__, DUMP5, DUMP4, DUMP3, DUMP2, DUMP1)(__VA_ARGS__)
template <typename T>
ostream &jout(T s, T e, string sep = " ", ostream &os = cout) {
  if (s != e) {
    os << *s;
    ++s;
  }
  while (s != e) {
    os << sep << *s;
    ++s;
  }
  return os;
}
ostream &yes(bool cond, string y = "Yes", string n = "No", ostream &os = cout) {
  os << (cond ? y : n) << endl;
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  return os << '(' << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t)
            << ')';
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  return jout(ALL(v), ", ", os << '[') << ']';
}
template <typename T>
ostream &operator<<(ostream &os, const set<T> &s) {
  return jout(ALL(s), ", ", os << '{') << '}';
}
template <typename K, typename V>
ostream &operator<<(ostream &os, const map<K, V> &m) {
  return jout(ALL(m), ", ", os << '{') << '}';
}
const ll INF = 1e18;
const ll MOD = 998244353;
#pragma endregion template
#pragma region mint 1.1
struct mint {
  ll a;

  mint(ll a = 0) : a((a % MOD + MOD) % MOD) {}
  mint pow(ll y) {
    ll exp = y;
    mint res = 1;
    mint p = a;
    while (exp) {
      if (exp & 1) {
        res *= p;
      }
      exp >>= 1;
      p *= p;
    }
    return res;
  }
  mint pow(mint y) { return pow(y.a); }
  mint &operator+=(ll y) {
    *this = a + y;
    return *this;
  }
  mint &operator+=(mint y) {
    *this += y.a;
    return *this;
  }
  mint &operator-=(ll y) {
    *this = a - y;
    return *this;
  }
  mint &operator-=(mint y) {
    *this -= y.a;
    return *this;
  }
  mint &operator*=(ll y) {
    *this = a * y;
    return *this;
  }
  mint &operator*=(mint y) {
    *this *= y.a;
    return *this;
  }
  mint &operator/=(ll y) {
    *this *= mint(y).pow(MOD - 2);
    return *this;
  }
  mint &operator/=(const mint y) {
    *this /= y.a;
    return *this;
  }
  mint &operator++() {
    *this += 1;
    return *this;
  }
  mint &operator++(int) {
    *this += 1;
    return *this;
  }
  mint &operator--() {
    *this -= 1;
    return *this;
  }
  mint &operator--(int) {
    *this -= 1;
    return *this;
  }
};

mint operator+(const mint &x, const mint &y) { return mint(x.a) += y; }
mint operator+(const mint &x, const ll &y) { return mint(x.a) += y; }
mint operator+(const ll &x, mint &y) { return mint(x) += y; }
mint operator-(const mint &x, const mint &y) { return mint(x.a) -= y; }
mint operator-(const mint &x, const ll &y) { return mint(x.a) -= y; }
mint operator-(const ll &x, const mint &y) { return mint(x) -= y; }
mint operator*(const mint &x, const mint &y) { return mint(x.a) *= y; }
mint operator*(const mint &x, const ll &y) { return mint(x.a) *= y; }
mint operator*(const ll &x, const mint &y) { return mint(x) *= y; }
mint operator/(const mint &x, const mint &y) { return mint(x.a) /= y; }
mint operator/(const mint &x, const ll &y) { return mint(x.a) /= y; }
mint operator/(const ll &x, const mint &y) { return mint(x) /= y; }
bool operator==(const mint &x, const mint &y) { return x.a == y.a; }
bool operator==(const mint &x, const ll &y) { return x.a == y; }
bool operator==(const ll &x, mint &y) { return x == y.a; }
bool operator!=(const mint &x, const mint &y) { return !(x == y); }
bool operator!=(const mint &x, const ll &y) { return !(x == y); }
bool operator!=(const ll &x, mint &y) { return !(x == y); }
istream &operator>>(istream &is, mint &i) {
  is >> i.a;
  return is;
}
ostream &operator<<(ostream &os, const mint &i) {
  os << i.a;
  return os;
}

typedef vector<mint> vm;
#pragma endregion mint

int main() {
  ll(N, K);
  vll(L, R, K);
  vm dp(N + 1);
  dp[1] = 1;
  repi(i, 2, N) {
    dp[i] = dp[i - 1];
    // dump(i);
    rep(j, K) {
      // dump(max(0LL, i - R[j]), max(0LL, i - L[j] - 1));
      // dump(dp[max(0LL, i - R[j])], dp[max(0LL, i - L[j] - 1)]);
      dp[i] += dp[max(0LL, i - L[j])] - dp[max(0LL, i - R[j] - 1)];
    }
  }
  // dump(dp);
  out(dp[N] - dp[N - 1]);
}


Measured memory_bytes: 4848