Memory

#include <bits/stdc++.h>
using namespace std;
#define fori(i,n) for(int i =0;i<n;i++)
#define pb push_back
#define ll long long
#define int long long
#define F first
#define S second
#define mp make_pair
#define rev(a) reverse(a.begin(),a.end())
#define srt(a) sort(a.begin(),a.end())
#define FAST ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);cout.precision(15);


int mod = 1000000007;

int pow(int a, int b) {
    int ans = 1;
    a %= mod;
    while(b) {
        if(b%2) {
            ans *= a;
            ans %= mod;
        }
        b /= 2;
        a *= a;
        a %= mod;
    }
    return ans;
}

std::vector<int> g[500005];
bool vis[500005];
int con=0,edges=0;

void dfs(int a) {
    stack<int> stc;
    stc.push(a);

    while(!stc.empty()) {
        int t = stc.top();
        stc.pop();
        vis[t] = 1;
        for(int i = 0;i<g[t].size();i++) {
            if (!vis[g[t][i]]) {
                vis[g[t][i]] = 1;
                stc.push(g[t][i]);
            }
        }
    }
}

int32_t main() {
    int n;
    std::vector<pair<pair<int,int>,int>> ranges;
    cin>>n;
    fori(i,n) {
        int x,y;
        cin>>x>>y;
        ranges.pb(mp(mp(x,y),i));
    }
    set<pair<int,int>> s;
    srt(ranges);

    fori(i,n) {
        auto it = s.lower_bound(mp(ranges[i].F.F,0));

        while (it != s.end() && it->F < ranges[i].F.S) {
            g[ranges[i].S].pb(it->S);
            g[it->S].pb(ranges[i].S);
            // cout<<endl<<it->S<<"   "<<ranges[i].S<<"   an edge";
            it++;
        }
        s.insert(mp(ranges[i].F.S,ranges[i].S));
    }
    ranges.clear();
    s.clear();

    fori(i,n) {
        edges += g[i].size();
        if(!vis[i]) {
            dfs(i);
            con++;
        }
    }

    if (edges/2 == n-1 && con == 1) {
        cout<<"YES";
    } else {
        cout<<"NO";
    }
    // cout<<"\n"<<edges<<"   "<<con;

}