#include 
#include 
using namespace std;

int solve(vector  celeb, int n){
	int result = -1, count, flagCeleb;
	for(int i = 1; i <= n; i++){
		vector  flag(n + 1, false);
		count = 0;
		int temp = i;
		while(!flag[celeb[temp]]){
			flag[celeb[temp]] = true;
			temp = celeb[temp];
			count++;
			if(count > result){
				result = count;
				flagCeleb = i;
			}
		}
	}
	return flagCeleb;
}

int main(){
	int n, a, b;
	vector  celeb;
	while(cin >> n){
		celeb.resize(n + 1);
		for(int i = 0; i < n; i++){
			cin >> a >> b;
			celeb[a] = b;
		}
		cout << solve(celeb, n) << endl;
		celeb.clear();
	}
	return 0;
}