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

#define mp make_pair
#define pb push_back
#define ll long long int
#define sd(x) scanf("%lld",&x)
#define inf 1000000000000000000
#define pll pair<ll,ll>
#define fastio ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define bits(x) __builtin_popcountll(x)
#define ld long double
#define test() ll test; cin>>test; while(test--)
#define fi first
#define se second


void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif


inline ll GCD(ll x, ll y) {
    if(x<y) swap(x,y);
    if(x==0) return y;
    if(y==0) return x;
    return GCD(x%y,y);
}

ll phi(ll n) {
    ll result = n;
    for (ll i = 2; i * i <= n; i++) {
        if(n % i == 0) {
            while(n % i == 0)
                n /= i;
            result -= result / i;
        }
    }
    if(n > 1)
        result -= result / n;
    return result;
}

ll power(ll x, ll n, ll mod) {
    ll res = 1;
    x %= mod;
    while(n) {
        if(n&1) {
            res = ((res*x)%mod+mod)%mod;
        }
        x = ((x*x)%mod+mod)%mod;
        n>>=1;
    }

    return res;
}

const int MAXN = 2e5+5;
const ll MOD = 998244353;

ll N,K;
ll L[11], R[11];
ll tree[4*MAXN]={0};
ll dp[MAXN]={0};

void update(ll node, ll start, ll end, ll l, ll r, ll val) {
    if(start>end || l>end || r<start) return;

    if(l<=start && end<=r) {
        tree[node]=val;
        return;
    }

    ll mid = (start+end)/2;
    if(l<=mid) update(2*node,start,mid,l,r,val);
    if(mid+1<=r) update(2*node+1,mid+1,end,l,r,val);

    tree[node] = tree[2*node]+tree[2*node+1];
}

ll query(ll node, ll start, ll end, ll l, ll r) {
    if(start>end || l>end || r<start) return 0;

    if(l<=start && end<=r) {
        return tree[node];
    }

    ll mid = (start+end)/2;

    ll left = 0, right =0;

    if(l<=mid) left = query(2*node,start,mid,l,r);
    if(mid+1<=r) right = query(2*node+1,mid+1,end,l,r);
    return left+right;
}

int main() {
    fastio;
    cin>>N>>K;

    for(ll i=1;i<=K;i++) {
        cin>>L[i]>>R[i];
    }


    dp[1]=1;
    update(1,1,N,1,1,dp[1]);
    for(ll i=2;i<=N;i++) {
        for(ll j=1;j<=K;j++) {
            ll l = max(0ll,i-R[j]);
            ll r = max(0ll,i-L[j]);

            dp[i] = (dp[i]+query(1,1,N,l,r))%MOD;
        }
        update(1,1,N,i,i,dp[i]);
    }
    cout<<dp[N]<<endl;
}




Measured memory_bytes: 9364