#include<bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp> //required
#include <ext/pb_ds/tree_policy.hpp> //required

using namespace __gnu_pbds; 
using namespace std;

template <typename T> using ordered_set =  tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; 
// find_by_order(k)  returns iterator to kth element starting from 0;
// order_of_key(k) returns count of elements strictly smaller than k;
typedef int  ll;
typedef vector<ll> VL;
typedef vector<int> VI;
typedef pair<ll,ll> PLL;
typedef pair<int,int> PII;
#define pb push_back

#define F first
#define S second
#define SZ(a) int((a).size())
#define ALL(a) a.begin(),a.end()
#define fr(i,x,y) for(int i=x;i<y;i++)
#define frr(i,x,y) for(int i=x-1;i>=y;i--)
//#define inf 1e18+1
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
const int mod=998244353;
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
ll power(ll a,ll b){ll ans=1;while(b!=0){if(b&1){ans*=a;}a=a*a;b>>=1;}return ans;}
ll powerm(ll a,ll b){ll ans=1;while(b!=0){if(b&1){ans*=a;ans%=mod;}a=a*a;a%=mod;b>>=1;}return ans%mod;}
VL dx={1,0,-1,0};
VL dy={0,1,0,-1};
// string to integer stoi()
// string to long long stoll()
// string.substr(position,length);
// integer to string to_string();

void solve()
{
    ll n,k;
    cin>>n>>k;
    VL arr;
    fr(i,0,k)
    {
        ll l,r;
        cin>>l>>r;
        fr(j,l,r+1)
        {
            arr.pb(j);
        }
    }
    sort(ALL(arr));
    VL dp(n+1,0);
    dp[1]=1;
    fr(i,1,n+1)
    {
        auto low=lower_bound(ALL(arr),i);
        if(low==arr.end())
        {
            low--;
        }
        if(*low>=i)
        {
            if(low==arr.begin())
                continue;
            else
            {
                low--;
            }
        }
        ll x=low-arr.begin();
        fr(j,0,x+1)
        {
            if(i-arr[j]<=0)
                break;
            dp[i]+=dp[i-arr[j]];
            dp[i]%=mod;
        }
    }
    cout<<dp[n]%mod<<endl;
    return;
}
int main()
{
    IOS;
    ll t=1,pp;
    //cin>>t;
    pp=t;
    while(t--)
    {
        //cout<<"Case #"<<pp-t<<": ";
        solve();
    }
    return 0;
}
/* stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
*/
/*
recursion - matrix exponential

*/
// BITMASK:
// 1)When some constrall is of the order of 15-20, think of bitmask DP.
// 2)When some constrall is around 40, try out meet in the middle
// 3) See Strings,palindromes,prefix,suffix etc -> KMP,Z algorithm