#include <bits/stdc++.h>
#define F first
#define S second
using namespace std;
using ll = long long;
using mint = long long;
typedef pair<int, int> P;
ll Mod = 998244353;

template< typename Monoid, typename OperatorMonoid, typename F, typename G, typename H >
struct LazySegmentTree {
  int sz, height;
  vector< Monoid > data;
  vector< OperatorMonoid > lazy;
  const F f;
  const G g;
  const H h;
  const Monoid M1;
  const OperatorMonoid OM0;

  LazySegmentTree(int n, const F f, const G g, const H h,
                  const Monoid &M1, const OperatorMonoid OM0)
      : f(f), g(g), h(h), M1(M1), OM0(OM0) {
    sz = 1;
    height = 0;
    while(sz < n) sz <<= 1, height++;
    data.assign(2 * sz, M1);
    lazy.assign(2 * sz, OM0);
  }

  void set(int k, const Monoid &x) {
    data[k + sz] = x;
  }

  void build() {
    for(int k = sz - 1; k > 0; k--) {
      data[k] = f(data[2 * k + 0], data[2 * k + 1]);
    }
  }

  inline void propagate(int k) {
    if(lazy[k] != OM0) {
      lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]);
      lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]);
      data[k] = apply(k);
      lazy[k] = OM0;
    }
  }

  inline Monoid apply(int k) {
    return lazy[k] == OM0 ? data[k] : g(data[k], lazy[k]);
  }

  inline void recalc(int k) {
    while(k >>= 1) data[k] = f(apply(2 * k + 0), apply(2 * k + 1));
  }

  inline void thrust(int k) {
    for(int i = height; i > 0; i--) propagate(k >> i);
  }

  void update(int a, int b, const OperatorMonoid &x) {
    if(a >= b) return;
    thrust(a += sz);
    thrust(b += sz - 1);
    for(int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if(l & 1) lazy[l] = h(lazy[l], x), ++l;
      if(r & 1) --r, lazy[r] = h(lazy[r], x);
    }
    recalc(a);
    recalc(b);
  }

  Monoid query(int a, int b) {
    if(a >= b) return M1;
    thrust(a += sz);
    thrust(b += sz - 1);
    Monoid L = M1, R = M1;
    for(int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if(l & 1) L = f(L, apply(l++));
      if(r & 1) R = f(apply(--r), R);
    }
    return f(L, R);
  }

  Monoid operator[](const int &k) {
    return query(k, k + 1);
  }

  template< typename C >
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while(a < sz) {
      propagate(a);
      Monoid nxt = type ? f(apply(2 * a + type), M) : f(M, apply(2 * a + type));
      if(check(nxt)) a = 2 * a + type;
      else M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }

  template< typename C >
  int find_first(int a, const C &check) {
    Monoid L = M1;
    if(a <= 0) {
      if(check(f(L, apply(1)))) return find_subtree(1, check, L, false);
      return -1;
    }
    thrust(a + sz);
    int b = sz;
    for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if(a & 1) {
        Monoid nxt = f(L, apply(a));
        if(check(nxt)) return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }
  
  template< typename C >
  int find_last(int b, const C &check) {
    Monoid R = M1;
    if(b >= sz) {
      if(check(f(apply(1), R))) return find_subtree(1, check, R, true);
      return -1;
    }
    thrust(b + sz - 1);
    int a = sz;
    for(b += sz; a < b; a >>= 1, b >>= 1) {
      if(b & 1) {
        Monoid nxt = f(apply(--b), R);
        if(check(nxt)) return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};

template< typename Monoid, typename OperatorMonoid, typename F, typename G, typename H >
LazySegmentTree< Monoid, OperatorMonoid, F, G, H > get_lazy_segment_tree
    (int N, const F &f, const G &g, const H &h, const Monoid &M1, const OperatorMonoid &OM0) {
  return {N, f, g, h, M1, OM0};
}

mint op(mint a,mint b) {
  return (a + b) % Mod;
}

mint e() {
  return 0;
}

mint id(mint a) {
  return a;
}

mint mapping(mint a,mint b) {
  return (a + b) % Mod;
}

mint compsition(mint a,mint b) {
  return (a + b) % Mod;
}

int main() {
  ll N;
  cin >> N;
  ll K;
  cin >> K;
  ll L[K],R[K];
  LazySegmentTree seg(N,op,mapping,compsition,0LL,0LL);
  seg.set(0,1LL);
  seg.build();
  for (int i = 0; i < K; i++) {
    cin >> L[i] >> R[i];
  }
  for (int i = 0; i < N-1; i++) {
    mint num = seg[i];
    for (int j = 0; j < K; j++) {
      int l = L[j] + i;
      int r = min(R[j] + i,N-1);
      if (l >= N) {
        continue;
      }
      seg.update(l,r+1,num);
    }
  }
  cout << seg[N-1] << endl;
  return 0;
}

Measured memory_bytes: 11448