#include <algorithm>
#include <climits>
#include <iostream>
#include <utility>
#include <vector>
using namespace std;

int main() {
	int ans = INT_MAX, tmp;
	size_t N;
	cin >> N;
	vector<pair<int, int>> AB(N);
	for (size_t i = 0; i < N; ++i) cin >> AB[i].first >> AB[i].second;
	sort(AB.begin(), AB.end());
	do {
		tmp = 0;
		for (size_t i = 1; i < N; ++i) tmp = max(tmp, AB[i - 1].second - AB[i - 1].first + AB[i].first);
		ans = min(ans, tmp);
	} while (next_permutation(AB.begin(), AB.end()));
	cout << ans;
}