#pragma GCC optimize ("O3")
#include <iostream>
#include <iomanip>
#include <istream>
#include <ostream>
#include <sstream>
#include <iterator>
#include <vector>
#include <algorithm>
#include <queue>
#include <deque>
#include <list>
#include <stack>
#include <map>
#include <unordered_map>
#include <set>
#include <bitset>
#include <utility>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <string>
#include <ctime>
#include <cctype>
#include <cstdlib>
#include <numeric>
#define IINF 1000000000
#define INF 3223372036854775807
#define MOD 1000000007
#define mod 998244353
#define INT_MAX_ 2147483647
#define EPS (1e-10)
#define REP(i, a, n) fo-r (ll i = a; i < (ll)(n); i++)
#define REPE(i, a, n) for (ll i = a; i <= (ll)(n); i++)
//#define rep(i,n)for (ll i = 0; i < (ll)(n); i++)
#define rep(i,l,r)for(ll i=(l);i<(r);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define Endl endl
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define eb emplace_back
#define mmax(x,y)(x>y?x:y)
#define mmin(x,y)(x<y?x:y)
#define chmax(x,y) x=mmax(x,y)
#define chmin(x,y) x=mmin(x,y)
#define all(x) (x).begin(),(x).end()
#define siz(x) (ll)(x).size()
#define PI acos(-1.0)
#define me memset
//#define bit(n,k) ((n>>k)&1)
#define lg length()
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;
typedef long double ld;
typedef pair<int,int>Pin;
typedef pair<ll,ll>Pll;
template<class T> using V=vector<T>;
template<typename T> using min_priority_queue = priority_queue<T, vector<T>, greater<T> >;
long long GCD(long long a, long long b) {return b?GCD(b,a%b):a;}
long long LCM(long long a, long long b) {return a/GCD(a,b)*b;}
ll pom(ll a,ll n,int m){ll x=1;for(a%=m;n;n/=2)n&1?x=x*a%m:0,a=a*a%m;return x;}
#define invp(a,p)pom(a,p-2,p)
int dx[4]={-1,0,1,0};
int dy[4]={0,-1,0,1};
int ddx[8]={-1,0,1,0,1,1,-1,-1};
int ddy[8]={0,-1,0,1,1,-1,1,-1};
ll cmp1(pair<Pll,ll> a,pair<Pll,ll> b){
        return a.fi.se>b.fi.se;
}
ll cmp2(pair<ll,ll> a,pair<ll,ll> b){
    if(a.fi!=b.fi)
        return  a.se<b.se;
    else
        return a.se>b.se;
}
//----------------------------------------------------------------------
struct mint{
    using ull=unsigned long long int;
    ull v;
    mint(ll vv=0){s(vv%mod+mod);}
    mint& s(ull vv){
        v=vv<mod?vv:vv-mod;
        return *this;
    }
    //オーバーロード
    mint operator-()const{return mint()-*this;}//符号反転
    mint&operator+=(const mint&val){return s(v+val.v);}
    mint&operator-=(const mint&val){return s(v+mod-val.v);}
    mint&operator*=(const mint&val){
        v=ull(v)*val.v%mod;
        return *this;
    }
    mint&operator/=(const mint&val){return *this*=val.inv();}
    mint operator+(const mint&val){return mint(*this)+=val;}
    mint operator-(const mint&val){return mint(*this)-=val;}
    mint operator*(const mint&val){return mint(*this)*=val;}
    mint operator/(const mint&val){return mint(*this)/=val;}
    mint pow(int n)const{
        mint res(1),x(*this);
        while(n){
            if(n&1)res*=x;
            x*=x;
            n>>=1;
        }
        return res;
    }
    mint inv()const{return pow(mod-2);}
    //拡張ユークリッドの互除法
    /* mint inv()const{
        int x,y;
        int g=extgcd(v,mod,x,y);
        assert(g==1);
        if(x<0)x+=mod;
        return mint(x);
    }*/
    friend ostream& operator<<(ostream&os,const mint&val){
        return os<<val.v;
    }//出力
    bool operator<(const mint&val)const{return v<val.v;}
    bool operator==(const mint&val)const{return v==val.v;}
    bool operator>(const mint&val)const{return v>val.v;}
};
const ll MAX = 2000010;//設定
mint fac[MAX], finv[MAX], inv[MAX];
// テーブルを作る前処理
void init(){
    fac[0] = fac[1] = 1;
    for(int i=1;i<MAX;i++)fac[i]=fac[i-1]*i;
    finv[MAX-1]=fac[MAX-1].inv();
    for(int i=MAX-2;i>=0;i--)finv[i]=finv[i+1]*(i+1);
    for(int i=MAX-2;i>=1;i--)inv[i]=finv[i]+fac[i-1];
}
//階乗
mint factor(ll n,ll k){
  if (n<k) return 0;
  if (n<0 || k<0) return 0;
  return fac[n]*finv[k];
}
// 二項係数計算
mint COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * finv[k] * finv[n - k];
}
ll modpow(ll a, ll n) {//a^n(MOD)を求める
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * a % mod;
        a = a * a % mod;//次の準備
        n >>= 1;
    }
    return res;
}
ll waru(ll a,ll b){
    return a*modpow(b,mod-2)%mod;
}

ll permutation(ll n,ll r)
{
    ll a=1;
    for(ll i=n-r+1;i<=n;i++)
        a*=i;
    return a;
}

ll nCr(ll n, ll r) {
    ll ans = 1;
    for (ll i = n; i > n - r; --i) {
        ans = ans*i;
    }
    for (ll i = 1 ; i < r + 1; ++i) {
        ans = ans / i;
    }
    return ans;
}

template <typename T>
struct BIT {
    int n;             // 要素数
    vector<T> bit[2];  // データの格納先
    BIT(int n_) { init(n_); }
    void init(int n_) {
        n = n_ + 1;
        for (int p = 0; p < 2; p++) bit[p].assign(n, 0);
    }
    void add_sub(int p, int i, T x) {
        for (int idx = i; idx < n; idx += (idx & -idx)) {
            bit[p][idx] += x;
        }
    }
    void add(int l, int r, T x) {  // [l,r) に加算
        add_sub(0, l, -x * (l - 1));
        add_sub(0, r, x * (r - 1));
        add_sub(1, l, x);
        add_sub(1, r, -x);
    }
    T sum_sub(int p, int i) {
        T s(0);
        for (int idx = i; idx > 0; idx -= (idx & -idx)) {
            s += bit[p][idx];
        }
        return s;
    }
    T sum(int i) { return sum_sub(0, i) + sum_sub(1, i) * i; }
    T query(int l, int r) { return sum(r - 1) - sum(l - 1); }
    int lower_bound(T w) { // a_1 + a_2 + ... + a_x >= w となるような最小の x を求める(ただし a_i >= 0)
    if (w <= 0) {
        return 0;
    } else {
        int x = 0, r = 1;
        while (r < n) r = r << 1;
        for (int len = r; len > 0; len = len >> 1) { // 長さlenは1段下るごとに半分に
            if (x + len < n && bit[x + len] < w) { // 採用するとき
                w -= bit[x + len];
                x += len;
            }
        }
        return x + 1;
    }
}
};

//----------------------------------------------------------------------
int main(int argc, char * argv[]){
    cin.tie(0);
    ios::sync_with_stdio(false);
    //-------------------------------  
    //ll begin_t=clock();
    //freopen("big.txt", "r", stdin);
    //freopen("out3.txt", "w", stdout);
    //------------------------------
    ll n,k;cin>>n>>k;
    V<Pll>LR(k);
    for(ll i=0;i<k;i++){
        cin>>LR[i].fi>>LR[i].se;
    }
    sort(all(LR));
    V<ll>s;
    for(ll i=0;i<LR.size();i++){
        for(ll j=LR[i].fi;j<=LR[i].se;j++){
            s.pb(j);
            //cout<<j<<endl;
        }
    }
    BIT<mint> bit(200020);
    //mint dp[200020];
    //dp[1]=1;
    bit.add(1,2,1);
    for(ll i=1;i<n;i++){
        /*
        for(ll j=0;j<s.size();j++){
            if(i+s[j]>n)break;
            dp[s[j]+i]+=dp[i];
        }
        */
        for(ll j=0;j<k;j++){
            //dp[LR[i].fi]+=dp[i];
            //dp[LR[i].se]-=dp[i];
            mint dpi = bit.sum(i)-bit.sum(i-1);
            //cout<<dpi<<endl;
            if(LR[j].fi+i>n)continue;
            bit.add(LR[j].fi+i,mmin(n,i+LR[j].se)+1,dpi);
        }
    }
    cout<<bit.sum(n)-bit.sum(n-1)<<endl;
    //------------------------------
    //fclose(stdin);
    //fclose(stdout);
    //ll end_t=clock();cout<<"time="<<end_t-begin_t<<"ms"<<endl;
    //------------------------------- 
    return 0;
}
//----------------------------------------------------------------------









































Measured memory_bytes: 54828