#include <iostream>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;

const int INF = static_cast<int>(2e9) + 1;

struct segment {
    int l, r;
};

int main() {
    int n;
    cin >> n;
    vector<segment> v(n);
    vector<pair<pair<int, int>, int>> events;
    for (int i = 0; i < n; ++i) {
        cin >> v[i].l >> v[i].r;
        events.push_back({{v[i].l, 1}, i});
        events.push_back({{v[i].r, 0}, i});
    }
    sort(events.begin(), events.end());
    set<pair<int, int>> opened;
    int ans = INF;
    int a = 0, b = 0;
    int balance = 0;
    for (int i = 0; i < 2 * n; ++i) {
        int x = events[i].first.first;
        int type = events[i].first.second;
        int index = events[i].second;
        if (type == 0) {
            if (balance > 0) ans = min(v[index].r - v[index].l, ans);
            opened.erase({v[index].l, index});
            if (!opened.empty()) {
                auto p = *(--opened.end());
                if (x - p.first < ans) {
                    ans = x - p.first;
                    a = index, b = p.second;
                }
            }
        } else if (type == 1) {
            opened.insert({x, index});
        }
    }
    if (ans != INF) {
        if (a > b) swap(a, b);
        cout << a + 1 << " " << b + 1 << "\n";
    } else {
        cout << "0\n";
    }
    return 0;
}