#include<iostream>

using namespace std;
int m, n, max;

int midnum(int n) {
	int a, b, c, m, x;
	a = log10(n);
	b = a % 2;
	c = a / 2;
	m = n;
	for (int i = 1; i <= c; i++)
		m /= 10;
	if (b == 1)
		x = m % 100;
	else
		x = m % 10;
	return x;
}
int main(){
	cin >> n;
	max = 0;
	for (int i=1;i<=n;i++)
	{
		cin >>m;
		if (midnum(m) > midnum(max)) max = m;
	}
	cout << max<<endl;
	system("pause");
	return 0;
}