#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define endl "\n"
#define pll pair<ll,ll>
#define vll vector<ll>
#define mll map<ll,ll>
#define fs first
#define sc second

const ll MOD = 1e9+7;

void dfs(ll p, vector<vector<ll>>& g, vector<bool> used, ll& ans, ll& ans_v, ll k)
{
	used[p] = true;
	if(k > ans)
	{
		ans_v = p+1;
		ans = k;
	}
	k++;
	for(ll i : g[p])
		if(!used[i]) dfs(i, g, used, ans, ans_v, k);
	k--;
}

void solve()
{
	ll n;
	cin >> n;
	vector<vector<ll>> g(n);
	vector<ll> top(n);
	for(ll i = 0; i < n; i++)
	{
		ll a, b;
		cin >> a >> b;
		g[a-1].push_back(b-1);
		top[b-1] = 1;
	}
	ll p = 0;
	for(ll i = 0; i < n; i++)
	{
		if(top[i] == 0)
		{
			p = i;
			break;
		}
	}
	vector<bool> used(n, false);
	ll ans = 0;
	ll ans_v = 0;
	ll k = 0;
	dfs(p, g, used, ans, ans_v, k);
	cout << ans_v << endl;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    ll t = 1;
    //cin >> t;
    while(t--)
        solve();
    return 0;
}