#include <bits/stdc++.h>
#define ull unsigned ll
#define ll long long
#define ld long double
#define INFL (ll)3e18
#define INF (int)2e9
#define MOD (ll)998244353
#define MODO (ll)(1e9+7)
using namespace std;

template<typename T>istream&operator>>(istream&is,vector<T>&v);
template<typename... Ts>istream&operator>>(istream&is,tuple<Ts...>& t);
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.first>>p.second;return is;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}
template<typename... Ts>istream& operator>>(istream& is, tuple<Ts...>& t) {apply([&](auto&... args) {((is >> args), ...);},t);return is;}

int main(void){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int n;
    cin >> n;
    map<int,vector<int>> e;
    vector<int> f;
    int a,b;
    for(int i = 0;i < n;i++){
        cin >> a >> b;
        e[a].push_back(b);
        f.push_back(a);
    }
    sort(f.begin(),f.end());
    set<int> r;
    deque<int> d;
    d.push_back(1);
    r.insert(1);
    while(!d.empty()){
        int t = d.front();
        d.pop_front();
        auto lb = lower_bound(f.begin(),f.end(),t);
        if(lb != f.begin()){
            lb = prev(lb);
            if(!r.count(*lb)){
                r.insert(*lb);
                d.push_back(*lb);
            }
        }
        if(e.count(t)){
            for(auto i:e[t]){
                if(!r.count(i)){
                    r.insert(i);
                    d.push_back(i);
                }
            }
        }
    }
    
    cout << *r.rbegin() << endl;
}