#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ff first
#define sd second
#define debug(x) cerr << #x << " ---> " << x << endl;
const int mxN = 2e6 + 5;
ll n,mod = 998244353,sz,val[mxN],str[mxN],nd[mxN];
pair<ll,ll> a[mxN];
struct ds{
vector<ll> par;
vector<vector<ll>> v;
vector<pair<ll,ll>> lr;
void init(){
v.resize(n + 5);
par.resize(n + 5);
lr.assign(n + 5, {0, 0});
for(int i = 0; i < n + 5; i++){
v[i].pb(i);
par[i] = i;
}
}
ll find(ll at){
if(par[at] == at) return at;
par[at] = find(par[at]);
return par[at];
}
void merge(ll a, ll b){
a = find(a);
b = find(b);
if(a == b) return;
sz--;
if(v[a].size() < v[b].size()) swap(a, b);
lr[a].ff = min(lr[a].ff, lr[b].ff);
lr[a].sd = max(lr[a].sd, lr[b].sd);
par[b] = a;
for(auto it : v[b]) v[a].pb(it);
v[b].clear();
v[b].shrink_to_fit();
}
};
struct segtree{
vector<vector<ll>> v;
ll sz = 1;
void init(){
while(sz < 2 * n + 5) sz *= 2;
v.resize(2 * sz);
}
void set(ll val, ll l, ll r, ll x, ll lx, ll rx){
if(lx >= r or rx <= l) return;
if(lx >= l and rx <= r){
v[x].pb(val);
return;
}
ll mid = lx + (rx - lx) / 2;
set(val, l, r, 2 * x + 1, lx, mid);
set(val, l, r, 2 * x + 2, mid, rx);
}
void set(ll val, ll l, ll r){
set(val, l, r, 0, 0, sz);
}
void find(ll i, vector<ll> &vv, ll x, ll lx, ll rx){
for(auto it : v[x]) vv.pb(it);
v[x].clear();
if(rx - lx == 1) return;
ll mid = lx + (rx - lx) / 2;
if(i < mid) find(i, vv, 2 * x + 1, lx, mid);
else find(i, vv, 2 * x + 2, mid, rx);
}
void find(ll i, vector<ll> &vv){
find(i, vv, 0, 0, sz);
}
};
void bfs(ll at, segtree &s){
queue<ll> q;
q.push(at);
while(!q.empty()){
at = q.front();
q.pop();
ll l = a[at].sd,r = a[at].ff;
vector<ll> v;
s.find(l, v);
s.find(r, v);
for(auto it : v){
if(val[it]) continue;
// cout << at << ' ' << a[at].sd << ' ' << a[at].ff << " ---> " << it << ' ' << a[it].sd << ' ' << a[it].ff << endl;
val[it] = 3 - val[at];
q.push(it);
}
}
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n;
segtree s;
ds ss;
s.init();
ss.init();
for(int i = 0; i < n; i++) cin >> a[i].sd >> a[i].ff;
sort(a, a + n);
for(int i = 0; i < n; i++) ss.lr[i] = {a[i].sd, a[i].ff};
sz = n;
for(int i = 0; i < n; i++){
ll l = a[i].sd,r = a[i].ff;
vector<ll> v;
s.find(l, v);
for(auto it : v) ss.merge(i, it);
ll at = ss.find(i);
s.set(at, ss.lr[at].ff, ss.lr[at].sd + 1);
}
ll ans = 1;
segtree s1;
s1.init();
for(int i = 0; i < n; i++) s1.set(i, a[i].sd, a[i].ff + 1);
for(int i = n - 1; i >= 0; i--) if(!val[i]){
val[i] = 1;
bfs(i, s1);
}
for(int i = 0; i < n; i++){
// cout << a[i].sd << ' ' << a[i].ff << ' ' << val[i] << '\n';
str[a[i].sd] = i + 1;
nd[a[i].ff] = i + 1;
}
stack<ll> st[3];
for(int i = 1; i <= 2 * n; i++){
// cout << i << ' ' << str[i] << ' ' << nd[i] << endl;
ll at;
if(str[i]){
// cout << " ---> " << i << endl;
at = str[i] - 1;
st[val[at]].push(at);
}
else{
at = nd[i] - 1;
// cout << at << ' ' << val[at] << ' ' << st[val[at]].top() << endl;
if(st[val[at]].top() != at){
cout << 0;
return 0;
}
st[val[at]].pop();
}
}
for(int i = 0; i < sz; i++) ans = ans * 2 % mod;
cout << ans;
}
