#include<bits/stdc++.h>
using namespace std;

#define real() cout<<"\n";

#define debug(arguments...) {string pri=#arguments;replace(pri.begin(),pri.end(),',',' ');stringstream prii(pri);istream_iterator<string> _iterat(prii);error(_iterat,arguments);}
void error(istream_iterator<string> _iterat) {}
template<typename T,typename...args>
void error(istream_iterator<string> _iterat,T a,args...arguments)
{
    cerr<<*_iterat<<"="<<a<<"\n";
    error(++_iterat,arguments...);
}

#define debugmp(z) {string pri=#z;error(pri,z);}
template<typename T,typename V>
void error(string pri,const pair<T,V> &z)
{
    cerr<<pri<<"="<<"{"<<z.first<<","<<z.second<<"}"<<"\n";
}
template<typename T,typename V>
void error(string pri,const map<T,V> &z)
{
    cerr<<pri<<" is={";
    for(auto it=z.begin();it!=z.end();++it)
    {
        cerr<<it->first<<":"<<it->second;
        auto _it=z.end();
        _it--;
        if(it!=_it) cerr<<",";
    }
    cerr<<"}";
    cerr<<"\n";
}

#define debugc(z,st,ed) {string pri=#z;error(pri,z,st,ed);}
template<typename T>
void error(string pri,const vector<T> &z,long long st,long long ed)
{
    cerr<<pri<<" in range["<<st<<","<<ed<<")=[";
    for(long long i=st;i<ed;++i)
    {
        cerr<<z[i];
        if(i!=ed-1) cerr<<" ";
    }
    cerr<<"]";
    cerr<<"\n";
}
template<typename T>
void error(string pri,const set<T> &z,long long st,long long ed)
{
    cerr<<pri<<" in range["<<st<<","<<ed<<")=[";
    long long tempcount=0;
    for(auto it=z.begin();it!=z.end();++it)
    {
        if(tempcount>=st and tempcount<ed)
        {
            cerr<<*it;
            if(tempcount!=ed-1) cerr<<" ";
        }
        tempcount++;
    }
    cerr<<"]";
    cerr<<"\n";
}
template<typename T>
void error(string pri,const T z[],long long st,long long ed)
{
    cerr<<pri<<" in range["<<st<<","<<ed<<")=[";
    for(long long i=st;i<ed;++i)
    {
        cerr<<z[i];
        if(i!=ed-1) cerr<<" ";
    }
    cerr<<"]";
    cerr<<"\n";
}

const long long mod=998244353;

void logic()
{
    long long n,k;
    cin>>n>>k;
    set<long long> temp;
    for(int i=0;i<k;++i)
    {
        long long x,y;
        cin>>x>>y;
        for(int j=x;j<=y;++j)
        {
            temp.insert(j);
        }
    }
    long long arr[n+1]={0};
    arr[0]=1;
    arr[1]=1;
    for(int i=2;i<=n;++i)
    {
        for(auto it=temp.begin();it!=temp.end();++it)
        {
            long long curr=*it;
            if(i-curr>0) arr[i]=(arr[i]+arr[i-curr])%mod;
            else break;
        }
    }
    cout<<arr[n];
    cout<<"\n";
    //incase of wrong answer...stress test your code...do not stress test yourself
    //overflow,bounds,size,constraints
    //sample tests,corner case/special case(n==0 or n==1 or negative numbers...),some hand written tests
    //read statement carefully
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    long long t;
    //cin>>t;
    //while(t--)
    {
        logic();
    }
}
