#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> P;
typedef pair<int,int> Pi;
#define rep(i,n) for(ll i=0;i<n;i++)
#define FOR(i,a,b) for(ll i=a;i<b;i++)
#define fi first
#define se second
#define endl "\n"

template<typename T> inline bool chmax(T &a, T b){if(a<b){a=b;return true;}return false;}
template<typename T> inline bool chmin(T &a, T b){if(a>b){a=b;return true;}return false;}
template<typename T> ostream& operator<<(ostream& s,const complex<T>& d) {return s<<"("<<d.real()<<", "<<d.imag()<< ")";}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const pair<T1,T2>& d) {return s<<"("<<d.first<<", "<<d.second<<")";}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& d){int len=d.size();rep(i,len){s<<d[i];if(i<len-1) s<<" ";}return s;}
template<typename T> ostream& operator<<(ostream& s,const vector<vector<T>>& d){int len=d.size();rep(i,len){s<<d[i]<<endl;}return s;}
template<typename T> ostream& operator<<(ostream& s,const set<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T> ostream& operator<<(ostream& s,const multiset<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const map<T1,T2>& m){s<<"{"<<endl;for(auto itr=m.begin();itr!=m.end();++itr){s<<" "<<(*itr).first<<" : "<<(*itr).second<<endl;}s<<"}"<<endl;return s;}

const ll mod=998244353;
const ll inf=1'000'000'000'000'000'00;
const int INF=1'000'000'000;
const double EPS=1e-10;
const double PI=acos(-1);

struct mint{
    ll x;
    mint(ll x=0):x((x%mod+mod)%mod){}
    mint& operator+=(const mint a){
        if((x+=a.x)>=mod) x-=mod;
        return *this;
    }
    mint& operator-=(const mint a){
        if((x+=mod-a.x)>=mod)x-=mod;
        return *this;
    }
    mint& operator*=(const mint a){(x*=a.x)%=mod;return *this;}
    mint operator+(const mint a) const{return mint(*this)+=a;}
    mint operator-(const mint a) const{return mint(*this)-=a;}
    mint operator*(const mint a) const{return mint(*this)*=a;}
    mint pow(ll t) const{
        if (!t) return 1;
        mint a=pow(t>>1);
        a*=a;
        if(t&1) a*=*this;
        return a;
    }
    // for prime mod
    mint inv() const{return pow(mod-2);}
    mint& operator/=(const mint a){return (*this)*=a.inv();}
    mint operator/(const mint a) const{return mint(*this)/=a;}
};
istream& operator>>(istream& is, mint& a) {return is>>a.x;}
ostream& operator<<(ostream& os, const mint& a) {return os<<a.x;}

struct combination{
    vector<mint> fact,ifact;
    combination(int n):fact(n+1),ifact(n+1){
        assert(n<mod);
        fact[0]=1;
        for(int i=1;i<=n;i++) fact[i]=fact[i-1]*i;
        ifact[n]=fact[n].inv();
        for(int i=n;i>=1;i--) ifact[i-1]=ifact[i]*i;
    }
    mint operator()(int n,int k){
        if (k<0 || k>n) return 0;
        return fact[n]*ifact[k]*ifact[n-k];
    }
};

struct LazySegmentTree{
private:
    int n;
    vector<ll> node,lazy;
    vector<bool> lazyFlag;
 
public:
    LazySegmentTree(){
        int sz=500050;
        n=1;
		while(n < sz) n*=2;
        node.resize(2*n-1,0);
        lazy.resize(2*n-1,0);
        lazyFlag.resize(2*n-1,false);
    }
    void build(const vector<ll> &v){
        int m=v.size();
        for(int i=0;i<m;i++) node[i+n-1]=v[i];
        for(int i=n-2;i>=0;i--) node[i]=(node[2*i+1]+node[2*i+2])%mod;
    }
    void lazyEvaluate(int k,int l,int r){
        if(lazyFlag[k]){
            node[k]+=lazy[k];
            node[k]%=mod;
            if(r-l>1) {
                (lazy[k*2+1]+=lazy[k]/2);
                (lazy[k*2+2]+=lazy[k]/2);
                lazyFlag[k*2+1]=lazyFlag[k*2+2]=true;
            }
            lazyFlag[k]=false;
            lazy[k]=0;
        }
    }
    void add(int a,int b,ll x,int k=0,int l=0,int r=-1){
        if(r<0) r=n;
        lazyEvaluate(k,l,r);
        if(b<=l || r<=a) return ;
        if(a<=l && r<=b) {
            (lazy[k]+=(x)*(r-l));
            lazyFlag[k]=true;
            lazyEvaluate(k,l,r);
        }
        else{
            add(a,b,x,2*k+1,l,(l+r)/2);
            add(a,b,x,2*k+2,(l+r)/2,r);
            node[k]=(node[2*k+1]+node[2*k+2])%mod;
        }
    }
    ll query(int a, int b, int k=0, int l=0, int r=-1) {
        if(r < 0) r = n;
        lazyEvaluate(k, l, r);
        if(b <= l || r <= a) return 0;
        if(a <= l && r <= b) return node[k]%mod;
        ll vl = query(a, b, 2*k+1, l, (l+r)/2);
        ll vr = query(a, b, 2*k+2, (l+r)/2, r);
        return (vl+vr)%mod;
    }
};

int main(){
    cin.tie(0);ios::sync_with_stdio(false);
    ll n,k;
    cin>>n>>k;
    vector<P> g(k);
    rep(i,k){
        cin>>g[i].fi>>g[i].se;
    }
    LazySegmentTree seg;
    seg.add(1,2,1);
    FOR(i,1,n){
        ll now=seg.query(i,i+1);
        for(auto [l,r]:g){
            seg.add(i+l,i+r+1,now);
        }
    }
    cout<<seg.query(n,n+1)<<endl;
}

Measured memory_bytes: 19844