#include <bits/stdc++.h>

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define FOR(i,n,m) for(int i=(int)(n); i<=(int)(m); i++)
#define RFOR(i,n,m) for(int i=(int)(n); i>=(int)(m); i--)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define setp(n) fixed << setprecision(n)

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

#define ll long long
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll,ll>
#define pi pair<int,int>

#define all(a) (a.begin()),(a.end())
#define rall(a) (a.rbegin()),(a.rend())
#define fi first
#define se second
#define pb push_back
#define ins insert

#define debug(a) cerr<<(a)<<endl
#define dbrep(a,n) rep(_i,n) cerr<<(a[_i])<<" "; cerr<<endl
#define dbrep2(a,n,m) rep(_i,n){rep(_j,m) cerr<<(a[_i][_j])<<" "; cerr<<endl;}

using namespace std;

template<class A, class B>
ostream &operator<<(ostream &os, const pair<A,B> &p){return os<<"("<<p.fi<<","<<p.se<<")";}
template<class A, class B>
istream &operator>>(istream &is, pair<A,B> &p){return is>>p.fi>>p.se;}

//-------------------------------------------------
//--ModInt
//-------------------------------------------------
const ::std::uint_fast64_t MOD = 998244353;

class mint
{
private:
    using value_type = ::std::uint_fast64_t;
    value_type n;
public:
    mint():n(0){}
    mint(::std::int_fast64_t _n):n(_n<0 ? MOD-(-_n)%MOD : _n%MOD){}
    mint(const mint &m):n(m.n){}

    friend ::std::ostream& operator<<(::std::ostream &os, const mint &a){
		return os << a.n;
	}
    friend ::std::istream& operator>>(::std::istream &is, mint &a){
        value_type temp; is>>temp;
        a = mint(temp);
        return is;
    }

    mint& operator+=(const mint &m){n+=m.n; n=(n<MOD)?n:n-MOD; return *this;}
    mint& operator-=(const mint &m){n+=MOD-m.n; n=(n<MOD)?n:n-MOD; return *this;}
    mint& operator*=(const mint &m){n=n*m.n%MOD; return *this;}
    mint& operator/=(const mint &m){return *this*=m.inv();}
    mint& operator++(){return *this+=1;}
    mint& operator--(){return *this-=1;}

    mint operator+(const mint &m) const {return mint(*this)+=m;}
    mint operator-(const mint &m) const {return mint(*this)-=m;}
    mint operator*(const mint &m) const {return mint(*this)*=m;}
    mint operator/(const mint &m) const {return mint(*this)/=m;}
    mint operator++(int){mint t(*this); *this+=1; return t;}
    mint operator--(int){mint t(*this); *this-=1; return t;}

    bool operator==(const mint &m) const {return n==m.n;}
    bool operator!=(const mint &m) const {return n!=m.n;}
    mint operator-() const {return mint(MOD-n);}

    mint pow(value_type b) const {
        mint ret(1), m(*this);
        while(b){
            if (b & 1) ret*=m;
            m*=m;
            b>>=1;
        }
        return ret;
    }

    mint inv() const {return pow(MOD-2);}
};

//-------------------------------------------------
//--Binary Indexed Tree (Sum only)
//-------------------------------------------------
template<typename T>
class BIT
{
private:
    const int n;
    ::std::vector<T> data;
public:
    BIT(int n):n(n),data(n+1){
        for(int i=1; i<=n; i++) data[i] = 0;
    }
    BIT(const ::std::vector<T> &v):n(v.size()),data(v.size()+1){
        for(int i=1; i<=n; i++) data[i] = v[i-1];
        for(int i=1; i<n; i++)
            data[i+(i&-i)] += data[i];
    }
    void add(int k, T x){k++;
        for(int i=k; i<=n; i+=i&-i) data[i] += x;
    }
    T query(int k){
        T ret=0;
        for(int i=k; i>0; i-=i&-i) ret += data[i];
        return ret;
    }
    T query(int a, int b){return query(b)-query(a);}
    void update(int k, T x){
        T upd = x-query(k, k+1);
        add(k, upd);
    }
    T operator[](int k){return query(k, k+1);}
};

const int N_MAX = 2e5;

//-------------------------------------------------

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N,K; cin>>N>>K;
    vi L(K),R(K);
    BIT<mint> bit(N+1);
    rep(i,K) cin>>L[i]>>R[i];
    rep(i,K) L[i]--;
    bit.add(0,1);
    bit.add(1,-1);
    rep(i,N){
        rep(j,K){
            bit.add(i+L[j], bit.query(i));
            bit.add(i+R[j], -bit.query(i));
        }
    }
    cout<<bit.query(N)<<endl;
    return 0;
}


Measured memory_bytes: 4760